SD3-60 AIRCRAFT MAINTENANCE MANUAL 21.pdf · 2015-08-25 · SD3-60 AIRCRAFT MAINTENANCE MANUAL...

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zSD3-60 AIRCRAFT MAINTENANCE MANUAL

AMM21-00-00 1.0.0.0AIR CONDITIONING - DESCRIPTION AND OPERATION

1. General

Refer to Figure 1.

A single air conditioning system supplies conditioned air to the flight and passenger compartments with separate temperature control for each.

The system derives its hot air from bleeds on both engines but will continue to work, with reduced performance on a supply from one engine only.

2. Bleed air conditioning

Refer to Figure 1. Refer to Figure 2 (Sheet 1).

Bleed air is taken via fixed orifices from the P2.5 and P3 bleed connections on each engine. At low power settings, when the P3 bleed pressure is below 35 p.s.i.g., the temperature control valve (TCV) is fully open admitting P3 bleed air only, to operate the system. At high power settings, when pressure in the P3 bleed line exceeds 35 p.s.i.g. a pressure switch operates to initiate modulation control via the solenoid selector valve and temperature sensor (TS), initially closing the TCV. Due to the absence of P3 pressure, the check valve in the P2.5 bleed line opens, maintaining system requirements on P2.5 bleed air only. Should the temperature in the common bleed line fall to below 300° F whilst operating on P2.5 bleed air, a temperature sensor (TS) will modulate the TCV to open, allowing P3 bleed air to mix with P2.5 thus maintaining the bleed air temperature above 250° F. To prevent spurious over-pressure warning being caused by a cold TS, a time delay is included to postpone the opening of the TCV until 10 seconds after the HA/SOV is selected open.

Downstream of the TS air passes through a hot air shut-off valve (HA/SOV), a venturi and a check valve to a common line. The check valves in each half system prevent cross-flow between engines and the dumping of all bleed air, should either duct fracture.

Air in the common line passes to a refrigeration unit consisting of a dual heat exchanger and a three-wheel air cycle machine (ACM). In the heat exchanger the bleed air is cooled in the primary section, compressed and then intercooled in the secondary section. The cooling medium in the heat exchanger is ambient air driven through the heat exchanger by the fan of the ACM. The NACA inlet for ambient air is located in the fuselage roof fairing. A flap at the top rear is spring-loaded closed and will open inwards to supplement the supply during static running should the demands of the ACM cause a partial depression within the fairing. A lip at the rear of the flap (aft hinge point) provides for aerodynamic assistance of flap closure during flight (in addition to spring action).

From the secondary section of the heat exchanger, the bleed air is ducted to the turbine inlet and to one half of a dual bypass valve; the outlets from both units combine and deliver the air to a water separator. The cooled air from the secondary section expands in the turbine and produces a low temperature and condensed mixture (fog); it also provides the power to drive the compressor and the fan. The water separator coalesces the fog into drops which, when



collected, are delivered as water to an aspirator which sprays into the cooling air stream of the heat exchanger.

Beyond the water separator, the ducting divides to provide for the various services detailed in para 4.

3. Bleed air control, indication and warning

A. HA/SOV control and indication

The left and right motorised HA/SOVs are each controlled by ON/OFF switch modules having integral line indication of valves open/shut condition on the AIR CONDITIONING panel 9P.

Line indication, which is controlled by 'travel limit' switches within each HA/SOV is provided by coloured strip lights in the cap of each module. On post-mod A8033 aircraft, indication of engine bleed point is given by P2.5 (Green letters)/P3 (yellow letters) indicators, one for each engine.

Power supplies for the left and right control switches are respectively taken from the 28V dc left shedding busbar and the 28V dc ground services busbar (via 5 amp circuit breakers Nos 90 and 211 on distribution panels 1D and 2D). The power supply for indication is taken from the 28V dc right essential services busbar via 5 amp circuit breaker No. 196 on distribution panel 2D.

The HA/SOVs will close automatically in the following contingencies:-

(1) When the Reserve Power System is activated for either engine a supply will be made available from the relevant reserve power relay to the 'close' field of the HA/SOV on that side.

(2) Each HA/SOV will close under the influence of its control relay (located on control panel 1C-left, 2C right) should the centre duct temperature exceed 525° F or the centre duct pressure exceed 35 p.s.i.g.

The initiating circuitry for the control relays is taken from a temperature sensor and an over-pressure switch situated upstream of the primary heat exchanger in the centre duct.



Air Conditioning SchematicFigure 1



When either the temperature or pressure switch settings are exceeded the respective switch contacts make to:-

(a) illuminate the BLEED air caption on the centralised warning panel and the duct OVERHEAT or OVER PRESSURE light on panel 9P as appropriate.

(b) energise the control relays which 'lock on' providing a supply to the 'close' field of the HA/SOV.

NOTE: The system is reset by tripping and resetting circuit breakers Nos 90 and 211 on respective distribution panels 1D and 2D when warning lights are extinguished i.e. bleed air temperature or pressure has returned to normal.

B. Spar box overheat warning

A thermostat is located in the centre-wing spar box bay left and right at station 68.80. Should the ambient temperature at either position rise to 110°C, possibly as a result of a leak in either the air-conditioning or aerofoil bleed air piping, the contact of the thermostat will close to illuminate:-

(1) The BLEED caption on the centralised warning panel 1P.

(2) The SPAR BOX OVERHEAT lights on panel 9P and the Anti-icing Services Panel 4P.

Power supplies for operation are taken from the 28V d.c. right essential services busbar, via C/B No. 196 on distribution panel 2D.

NOTE: Upon receipt of a warning, the crew adopt a drill to determine and isolate the source of seepage.

C. Duct low pressure warning

Warning of duct low pressure is afforded by three LP switches, two of which sense the pressure of the bleed air ducting immediately downstream of the venturi in each half system and the other sensing the pressure in the common (centre) duct upstream of the primary heat exchanger.

Each switch 'breaks' on a rising pressure not greater than 6 p.s.i.g. and 'makes on' a falling pressure less than the break pressure but not less than 5 ± 0.25 p.s.i.g.

Power supplies for signalling operation are taken from the 28V d.c. right essential services busbar via C/B No. 196 on distribution panel 2D.

The LP switch in each half system is wired in parallel with the LP switch in the centre duct and becomes operational only when the HA/SOV is fully open ie. the valve's limit switch has tripped (open) providing power to operate the LP circuit control relay.



With flow in both half systems, should the pressure at any of the three LP switches fall below the make pressure, a supply will be completed to illuminate the BLEED caption on the centralised warning panel and the DUCT LOW PRESSURE warning light on panel 9P.

When there is flow in one half system only, the warning lights will illuminate should either the LP switch in that half system or in the common duct fall below the make setting.

D. Duct overpressure warning

A high pressure switch is tapped into the centre duct upstream of the primary heat exchanger. The HP switch makes on a rising pressure of 35 ± 1 p.s.i.g. and breaks on a falling pressure less than the make pressure but not less than 29 p.s.i.g.

NOTE: To avoid initial surge activation of overpressure warning, a 3 second interval should be observed between ON selection of both engine bleeds.

Should the make pressure be operationally exceeded as a result of a system malfunction a supply will be completed to illuminate the BLEED caption on the centralised warning panel and the duct OVER PRESSure light on panel 9P. Power supplies for operation are taken from the 28V dc right essential services busbar via C/B no. 196 on distribution panel 2D.

Upon a receipt of a warning, the crew adopt a drill to identify and isolate the faulty HA/SOV.

4. Air conditioning services

NOTE: On 300F series aircraft (post-mod A8593), all reference to passenger compartment services are to be ignored.

- Pre Mod A8593 Air Conditioning Control Panel 9P - Refer to Figure 2 (Sheet 1).- Post Mod A8593 Air Conditioning Control Panel 9P - Refer to Figure 2 (Sheet 2)).

The deleted services on Figure 2 (Sheet 2) are inhibited.

A. Flight compartment conditioned air

A cold air tapping is taken from downstream of the water separator and is connected to a hot bleed air junction controlled by an electrically operated, single/dual (-300F series aircraft bypass valve. The junction forms an ejector type mixer and is connected to a distribution duct which supplies two floor level distributors located on the left and right of the flight compartment. The conditioned air enters the flight compartment through a series of holes in the forward faces of each floor level distributor. The air flow is controlled by manually operated butterfly valves located at the aft end of each distributor. The valves are identified CABIN HEAT - ON/OFF.



A temperature sensor and a duct overheat switch are located in the common duct to the flight compartment. The temperature control is described in para 6.

NOTE: Except for -300F series aircraft, conditioned air from the passenger compartment system is available through two gaspers located on the flight compartment aft bulkhead. See para 4.C.

B. Windshield and side window demisting

Two tappings are taken from the flight compartment conditioned air duct and routed to a manually controlled butterfly valve located at either side of the flight compartment on the forward face of station 74 at rear window height. The valves are identified DEMIST - ON/OFF and control the demist air flow to the flight compartment side windows and windshields.

C. Passenger compartment conditioned air

A cold tapping is taken from downstream of the water separator and is connected to a mixing box. Hot bleed air is also connected to the mixing box through one half of an electrically controlled dual bypass valve.

The mixing box forms an ejector type mixer and supplies conditioned air to a distribution duct. The temperature of the conditioned air is determined by the amount of bleed air allowed to enter the mixing box via the dual bypass valve.

The distribution duct delivers warm conditioned air to the left and right floor level distributors or cold conditioned air to the left and right ceiling level distributors. The conditioned air enters the passenger compartment through a series of holes in the face of each distributor.

The distribution of conditioned air to either the floor level distributors or the ceiling level distributors is controlled by two manually operated valves located on the left and right of the flight compartment aft bulkhead. Each valve has two positions:-

(1) SUMMER - with the control lever in this position the duct to the floor level distributors is blocked off and cold conditioned air is delivered to the ceiling level distributors.

(2) WINTER - with the control lever in this position the duct to the ceiling level distributors is blocked off and warm conditioned air is supplied to the floor level distributors.

Two tappings are taken from the common duct to the passenger compartment and are connected to two gaspers, one located on the right and one on the left of the flight compartment aft bulkhead. The gaspers provide a secondary source of air conditioning for the flight compartment.

D. Compartment Anti-Fog System

NOTE: On 300F series aircraft (post mod A8593) subsequent reference to passenger compartment in the following text is to be read as flight compartment.



In hot, humid conditions, with the air conditioning system operating in the full cooling mode fogging may appear in the passenger compartment.

This condition ensues when the passenger compartment duct sensor detects an actual temperature several degrees higher than that at the water separator inlet, modulating both portions of the dual by-pass valve to close. This may cause the water separator to freeze, thus activating its integral by-pass and permitting turbine delivered fog from the ACM to enter the compartment.

In this contingency the ANTI-FOG ON/OFF switch (panel 9P) which series-links a 33K.ohm resistor with the duct sensor and passenger compartment controller is selected ON.

This will bring the duct sensed temperature, in the full cooling mode to approximate more closely to that of the water separator.

The sensor will then signal the low temperature limiting circuitry of the controller to modulate the dual by-pass valve such that the water separator inlet temperature remains above 35° F.

The ANTI-FOG ON/OFF switch should not be switched ON in normal conditions, so that, in the heating mode, the passenger compartment duct temperature upper limit of 160° F (71°) remains effective and full advantage of the cooling mode is available when fog would not ensue.

E. Individual ventilation

(1) Passenger compartment

Individual ventilation is provided by air outlets (gaspers) located on the passenger service units (PSUs). The PSUs are located above the seats on each side of the passenger compartment. The right hand side PSUs have double gasper installations. Each gasper comprises a manually operated butterfly valve which is opened and closed by a knurled ring located on the bottom of each gasper.

Two cold air tappings are taken from downstream of the water separator. One tapping is connected, via a flap valve, to the right gasper system and the other is connected, via a second flap valve, to the left gasper system. The flap valves prevent feed back from the gasper fans.



Control Panel 9P (Pre-mod A8593)Figure 2 (Sheet 1)



Control Panel 9P (Post-Mod A8593)Figure 2 (Sheet 2)



(2) Flight compartment

Two gaspers, one for the left side and one for the right side, are located on the main instrument panel 1P and provide cool, conditioned air for the flight compartment.

Pre Mod A8593

The cool air for the flight compartment gaspers is tapped from the left and right supply to the passenger compartment. The tappings are taken downstream of each flap valve and are connected to the associated gasper via a collector box. The collector box prevents ingress of water and/or condensation when the gasper boost system is in operation. See para 4.F.(2).

Post Mod A8593

From the two tappings in the water separator outlet duct, cold air is ducted to either side of the aircraft to individual gaspers positioned in the flight deck. There is no gasper ram/fan system.

F. On-ground ventilation

On-ground ventilation, with engines shut down, may be taken from any of the following independent sources.

(1) Main Fan

The fan, situated within the fuselage roof between stations 74 and 137 supplies ambient air via a tapping in the main ducting immediately downstream of the water separator. A shut-off valve in the fan duct prevents back flow through the fan when the normal air conditioning is operating.

(a) Shut-off valve

The shut-off valve idented HR6, is actuated by a split field (open-shut) series wound motor, incorporating limit switches which prevent overtravel and control an indicator module displaying line indication of valve open/shut condition.

(b) Power supplies and control

Electrical power is derived from the 28V dc ground services busbar (right) via a 5 amp circuit breaker No. 211 (for shut-off valve operation) and a 25 amp circuit breaker No. 212 (for fan operation) on distribution panel 2D.

Control is by a three position switch ON-RAM-OFF on AIR CONDITIONING panel 9P.

The control circuitry is such that, following an ON selection at the control switch, power will not be available to drive the fan until the control valve is fully opened (limit



switch tripped). The fan circuit is also subject to the overriding authority of the landing gear weight switch and is operational on ground only.

In flight, the control valve may be opened (RAM selection) as a boost to the bleed air flow or to provide an alternative supply of air at ambient conditions following a total loss of bleed air.

(2) Gasper boost system (Pre-Mod A8593 only)

Refer to Figure 1

A gasper boost unit is sitted on either side of the aircraft within the fuselage roof structure between stations 89 and 146 and is employed to increase flow from the gaspers when the aircraft is on the ground or to provide gasper supply in periods of flight (take-off and landing) when normal air conditioning is unavailable (engine bleeds OFF).

(a) Left installation

The left sub-system is served by an intake scoop mounted on the fuselage side wall at station 89. The supply ducting, fitted upstream of the collector box incorporates a gasper boost control valve, a fan and a flap valve.

The flap valve is employed to prevent back-flow when the fan (which is utilised for ground use only) is operating.

Beyond the collector box, flexible distribution ducting is routed through the fuselage sidewall to the flight and passenger compartment gaspers, located respectively on main instrument panel 1P and the passenger service units.

A branch pipe from the flight compartment distribution duct incorporates a flap valve which closes when the boost system is in use and open to permit 'aircraft en-route' delivery of conditioned air when the basic air-conditioning system is operating.

(b) Right installation

The right sub-system is similar to the left, except that two fans are fitted in series to ensure that adequate delivery velocity is available from the double gasper installations on this side.

(c) Gasper boost shut-off valves

The valves, idented 1HM4 - left and 2HM4 - right are actuated by a split field (open - shut) series wound motor and incorporate limit switches to prevent over-travel. Indicator modules on panel 9P are controlled by the limit switches and display line indication of the appropriate valves open/shut condition.

For valve control aspects - refer to para 4.F.(2)(e).



(d) Power supplies and controls

Power supplies are derived from the 28V dc Ground Services Busbar via 5 amp circuit breakers Nos 209 and 211 (for boost control valve operation) and a 15 amp circuit breaker No. 210 (for fan operation) on distribution panel 2D.

Control is by a three position switch ON-RAM-OFF on the AIR CONDITIONING panel 9P.

(e) Operation

With power made available (para (d)) and the aircraft on the ground, selection of the control switch on panel 9P to ON will operate all three fans and provide appropriate 'on line' indication when each boost shut-off valve has reached the fully open position (limit switch tripped). Fan inducted ambient air will then be available to the gaspers.

The fans will operate throughout the take-off run until the supply is interrupted by weight switch action when the aircraft becomes airborne. Operationally the switch is left at ON (thus admitting ram air via the open boost valves) until conditioned air is again made available i.e. engine bleeds are opened. The switch is then selected OFF providing subsequent 'off line' indication when the valve is fully closed (limit switch tripped).

(3) Recirculation/Ground inlet fan (pre-mod A8593 only)

The fan, which is situated within the fuselage roof between stations 137 and 179 may be used in the recirculation or ground inlet modes in hot, humid conditions to augment the movement of air within the passenger compartment.

(a) Recirculation

In the recirculation mode the fan draws air through the kicking strip ducts and delivers it back to the passenger compartment via the high level ducts. Recirculation may be selected on in flight to supplement the normal air conditioning.

(b) Ground inlet

In the ground inlet mode the fan draws ambient air through a grille in the fuselage roof and delivers it directly to the high level ducts. This facility is for ground use only and should not be selected on in flight.

(c) Control valves

The valves, idented 2H53 (recirculation) and 1H53 (ground air) are actuated by split field (open-shut) series wound motors and incorporate limit switches to prevent over-travel. Indicator modules on Panel 9P are controlled by the limit switches and display line indication of the appropriate valves open/shut condition.



(d) Power supplies and controls

Electrical supplies are derived from the 28V dc ground services busbar via a 5 amp circuit breaker No. 208 (for control valve operation) and a 10 amp circuit breaker No. 207 (for fan operation) on distribution panel 2D. Control is by a GND AIR - RE-CIRC-OFF switch on panel 9P.

(4) Ground connection

When in extreme climatic conditions, conditioned air may be supplied to the aircraft via a ground connection using a suitable Ground Service Unit (G.S.U.).

The ground connection is tapped into the right vertical duct between stations 74 and 89, 15.6 in. above the water line.

Air is delivered from the G.S.U. with the right S/W valve set at WINTER and the left S/W valve set at SUMMER. Conditioned air is then delivered to the pass. compt. via the right kicking strip and left high level duct. An orifice plate contained in the ground connection prevent the aircraft from being over-pressurised by the G.S.U.

5. Extraction system

A. Passenger compartment

The majority of passenger compartment air is extracted via a grille on top of the galley unit and is ducted to an under-floor louvred outlet in the aft baggage compartment, where it is discharged overboard.

A portion of the passenger compartment air is extracted through grilles above the forward-facing overhead lockers at the rear, passes through the toilet compartment and aft bulkhead grilles to be discharged through a separate underfloor outlet in the aft baggage compartment.

B. Flight compartment

Air is extracted from the compartment via a grille positioned on the upper left hand side of the rear bulkhead from which flexible ducting is routed to a louvred outlet on the aircraft bottom skin below the left side of the pass. compt. A similar louvred outlet on the opposite side provides extraction for the equipment bays below the flight compartment floor.

6. Temperature control (Flight and passenger compartment)

NOTE: On 300F series aircraft (post-mod A8593) passenger compartment conditioned air distribution is inhibited; ducting is blanked and the supply re-directed to the flight compartment services.

The temperature controller hitherto associated with the passenger compartment is used in conjunction with the dual bypass valve and flight compartment temperature sensors to control flight compartment temperature. Flight Attendants Panel 12P is not fitted on - 300F series aircraft.



The passenger compartment automatic temperature control system consists of a controller (electronic analogue type computer) a temperature selector and two temperature sensors, one within the compartment and the other in the supply duct. The controller compares the selected temperatures with the compartment and duct sensed temperature and modulates the dual by-pass valve accordingly. A similar system in the flight compartment modulates the single bypass valve.

The AUTO TEMPerature selector switch on the pilot's control panel 9P is duplicated on the flight attendant's panel 12P and becomes operational by the flight attendant only when the AUTO CONTROL PILOT/ATTD'T switch (9P) is selected to ATTD'T.

The duct temperature sensors in the flight and passenger supply ducts downstream of the hot line connections additionally signal the temperature controllers to limit respective duct temperatures throughout the conditioning range of operation (auto mode) to between 35° F (2° C) and 160° F (71° C).

The lower limit is of particular importance with regard to the passenger compartment controller, ensuring that delivery air to the water separator is maintained above freezing point.

If a failure occurs and the upper temperature limit is exceeded, an overtemperature switch in the appropriate duct will illuminate the BLEED air caption on the centralized warning panel and the associated duct OVERHEAT light on the AIR CONDITIONING services panel 9P.

NOTE: The passenger compartment overtemperature switch operates when the duct temperature reaches 185° F to 195° F (85° C to 90° C) and the flight compartment switch at 235° F to 245° F (113° C to 118° C).

Receipt of an overheat warning is a signal to select the affected systems mode switch on panel 9P from AUTO to MANUAL (thus isolating the controller). Operation of the appropriate bypass valve (dual or single) will then be subject to the control of the associated HOT/COOL manual control switch on panel 9P; this switch is held momentarily in the required position to modulate the relevant bypass valve.

On aircraft post Service Bulletin SD360-21-13, crew indication of the ambient temperature in the passenger compartment is provided by a temperature gauge on panel 9P. Refer to 21-61-00, pb1.



AMM21-00-01 2.0.0.0GASPER BOOST SYSTEM - MAINTENANCE PRACTICES

1. Adjustment/Test

A. Function check the system

(1) Provide electrical power and close C/B No. 209, 210 and 211 on distribution panel 2D. Refer to 12-09-03, pb301.

(2) With the control switch OFF/RAM/ON on panel 9P set at OFF, check that the left and right gasper boost valves are shut (indicator modules display off-line).

(3) Select control switch to RAM and check that both valves (indicator modules display in-line).

(4) Fully open gasper units on flight compartment panel 1P and along the left and right sides of passenger compartment.

(5) Advance control switch to ON and check that all three fans are activated i.e. balanced delivery velocity of inducted air is available between the left and right hand sides of the compartments at corresponding lateral positions.

(6) Check fan flight inhibiting circuitry as follows:-

WARNING: ENSURE THAT GROUND LOCKING PINS ARE FITTED TO THE LANDING GEAR, PREVENTING RETRACTION, SHOULD THE SELECTOR SWITCH BE OPERATED INADVERTENTLY DURING OPERATION (D).

(a) Gain access to TB74, situated in the right landing gear bay (Stn.316), by removing the access panel from the bulkhead.

(b) With fan selected ON, connect a switchable 28V d.c. power supply (control switch open) to the coil of the weight switch relay via terminal No.2 on TB74.

(c) Close the power supply control switch, thus energising the coil of the weight switch control relay and check that flow from the gaspers has ceased - fans deactivated.

(d) Disconnect power supply and replace access panel.



AMM21-00-06 3.0.0.0HEAT EXCHANGER - MAINTENANCE PRACTICES

1. Removal/Installation

Refer to Figure 201.

A. Remove a heat exchanger.

(1) Remove access panels 240 AR, 240 BR, 240 AL, 240 BL, 240 CL, 240 DL and 240 EL on forward fairing. Refer to 6-30-00, pb1.

(2) Remove detachable fairing structure between frame stations 74 and 179.8. Note positions and method of attachments for subsequent re-installation.

(3) Disconnect ducting as follows:-

(a) Heat exchanger to air cycle machine (detail C)

(b) Heat exchanger to compressor inlet (detail A)

(c) Heat exchanger to turbine and by-pass valve (detail A).

(d) Compressor to heat exchanger (detail A)

(e) Engine supply duct to heat exchanger (detail B)

(4) Disconnect drain tube from heat exchanger.

(5) Detach heat exchanger and channel assemblies where secured to vertical support posts.

(6) Remove unit complete with channel assemblies.

NOTE: Slacken adjacent ducting as necessary to negotiate removal of heat exchanger noting positions for re-tightening during subsequent re-installation.

B. Install a heat exchanger

NOTE: Operation (1) only applies if unit is not that previously removed (para 1.A.).

(1) Remove the four bolts, nuts and washers which secure the channel assemblies, gasket and duct to the top of the heat exchanger and fit these items to the replacement unit.

(2) Install heat exchanger with top channel assemblies to support posts and attach using bolts nuts and washers.

NOTE: At aft inboard corner two vertical bolt positions to be left redundant until forward fairing is installed.

(3) Connect drain tube to heat exchanger and tighten jubilee clip.



Heat Exchanger - Removal/InstallationFigure 201



(4) Refer to Figure 201. Make the following ducting connections with reference to the appropriate detail using new 'O' ring seals where required.

(a) Heat exchanger to air cycle machine (detail C).

(b) Compressor to heat exchanger (detail A) using seal Pt. No. 56A 460 225.

(c) Engine supply duct to heat exchanger (detail B).

(d) Heat exchanger to turbine by-pass valve (detail A) using seal Pt. No. 56A 460 175.

(e) Heat exchanger to compressor inlet (detail A) using seal Pt. No. 56A 460 250.

(5) Refit fairing detachable structure between frame stations 74 and 179.8 securing as noted during removal operations.

(6) Install access panels 240 AR, 240 BR, 240 AL, 240 BL, 240 CL, 240 DL and 240 EL on forward fairing.



AMM21-00-11 4.0.0.0AIR CYCLE MACHINE - MAINTENANCE PRACTICES

1. Servicing

A. Check oil level in sump

(1) Open access panel 240 DL in forward fairing on fuselage roof.

(2) By the use of a mirror inspect the oil level sight plug, situated on the forward side of the air cycle machine beneath the outlet ducting, to ensure that the sight bulb is full of oil.

(3) Close access panel 240 DL.

B. Replace oil in sump

(1) Remove access panel 240 DL in forward fairing on fuselage roof.

(2) Break locking wire of filler plug, adjacent to oil level sight plug, and remove filler plug and pre-formed packing. Retain filler plug and discard packing.

(3) Siphon-drain sump through filler plug orifice.

(4) Fill sump to filler port level with Exxon 2380 oil.

NOTE: Exxon 2380 oil per MIL-L-23699 is the recommended lubricant for maximum service life. If not available MIL-L-7808G is suggested for use in cooler climates and other oils per MIL-L-23699 for operation in warmer climates.

(5) Install filler plug and new pre-formed packing 69494 K11 and tighten to 15 to 25 lb.in. torque.

(6) Wire lock plug to sump.

(7) Replace access panel 240 DL.


A. Remove an air cycle machine (ACM)


(1) Open circuit breaker No. 196 on right distribution panel 2D.

(2) Remove access panels 240 AL, 240 CL, 240 DL and 240 EL in forward fairing on fuselage roof.

(3) Disconnect bayonet type electrical connection from over temperature switch.



(4) Disconnect the following ducts at the air cycle machine:-

- ACM turbine outlet (detail A)- Heat exchanger to compressor inlet (detail A)- Compressor outlet to heat exchanger (detail A).- ACM turbine inlet (detail B).- ACM to heat exchanger (detail C).

(5) Remove split pins, nuts, washers and bolts holding ACM to mounting platform, and retain.

(6) Remove bushes from inboard attachment holes and retain.

(7) Lift ACM clear and remove from aircraft.

NOTE: Slacken adjacent ducting as necessary to negotiate removal of ACM noting positions for re-tightening during subsequent re-installation.

B. Install an air cycle machine

NOTE: Operation (1) only applies if unit is not that previously removed in para 2.A.

(1) If ACM is unserviceable, transfer turbine outlet elbow and attachments to replacement ACM, using HYLOMAR jointing compound Part No. SQ32.

NOTE: Alternatively a gasket, Hamilton Standard Part No. 753443-2 may be substituted for the jointing compound;

(2) Align ACM with attachment holes in mounting platform and fit bushes to the two inboard holes, with the bush flanges on the outboard side. All bolts to be entered from outboard side, washers fitted under nuts, nuts tightened and split pinned.

(3) Refer to Figure 201. Make the following duct connections with reference to the appropriate detail using new 'O' ring seals as required:-

- ACM to heat exchanger (detail C).- ACM turbine inlet (detail B) using seal Part No. 69494-J-132.- Compressor outlet to heat exchanger (detail A).- Heat exchanger to compressor inlet (detail A).- ACM turbine outlet (detail A).

(4) Reconnect bayonet type electrical connection to over temperature switch.

(5) Replace access panels 240 AL, 240 CL, 240 DL and 240 EL.

(6) Close circuit breaker No. 196 on right distribution panel 2D.



Air Cycle Machine - Removal/InstallationFigure 201



AMM21-00-16 5.0.0.0WATER SEPARATOR - MAINTENANCE PRACTICES

1. Servicing

A. Clean a coalescer

(1) Remove from water separator as detailed in para 2.C.

(2) Mix a solution of 2 ounces of Basic 1 (Shaklee Products, Hayward, Calif.) in 1.0 gallon of water heated to 100 to 130 degrees F (38 to 54 degrees C).

(3) Soak the coalescer approximately 15 minutes. Rinse in a clean solution of Basic 1 and water by dipping in the solution approximately 20 to 30 times to flush away loose dirt.

NOTE: Do not twist or agitate as this will cause the nap to 'pill' or 'ball'.

(4) Rinse a second time in clean, warm water and press excess water out after rinsing.

(5) Repeat (2) to (4) inclusive.

(6) Hang to dry at room temperature. May be drop dried or water may be pressed out prior to drying.

(7) Refit coalescer as detailed in para 2.D.


A. Remove a water separator


(1) Remove access panels 240 AR and 240 BR on forward fairing.

(2) Make the following disconnections leaving ducts loosely in approximate installation positions to ease subsequent re-installation of water separator.

- Inlet duct to unit (detail A)- Outlet duct from unit (detail A)- Drain tube from unit

(3) Unscrew nuts from T-bolt latch on straps.

(4) Remove water separator.

B. Install a water separator


(1) Set the unit into cradles and install to suit ducts.



(2) Fit securing straps and secure T-bolt latches with nuts.

(3) Make the following ducting connections with reference to the appropriate detail.

- Outlet duct from unit (detail A)- Inlet duct to unit (detail A)- Drain tube from unit

C. Remove the coalescer

(1) Remove access panel 240 BR on forward fairing.

(2) Loosen and remove grooved clamp from water separator.

(3) Remove end cap from water separator. Retain preformed packing if undamaged.

(4) Remove coalscer by lifting away from screen being careful not to tear the fabric.

D. Install the coalescer

(1) Install the coalescer over screen being careful not to tear the fabric. Assure that the nap side of the fabric is facing the inboard side of the housing.

(2) Fit end cap to water separator using preformed packing Part No. 69494 J446 (Hamilton Standard).

(3) Fit groove clamp to attach end cap to water separator and torque tighten to 20 to 25 pound-inches.

(4) Install access panel 240 BR on forward fairing.



Water Separator - Removal/InstallationFigure 201



AMM21-00-21 6.0.0.0RAM/MAIN FAN - MAINTENANCE PRACTICES



A. Remove a ram/main fan.

(1) Isolate electrical supply by opening C/B No. 211 on distribution panel 2D.

(2) Remove access panel 240 AR and 240 BR on forward fairing. Refer to 6-30-00, pb1.

(3) Unscrew electrical connection from unit.

(4) Remove nuts, bolts, washers and gasket from downstream duct flange (detail A).

(5) Unscrew flange clamp at inlet end of unit (detail B).

(6) Unscrew nut from T-bolt latch on strap holding unit.

(7) Remove unit.

B. Install a ram/ main fan.

NOTE: Operation (1) only applies is unit is not that previously removed in para. 1.A.

(1) If unit is unserviceable remove adaptor from inlet end by removing six nuts, bolts and washers, attach adapter to replacement unit making sure that gasket is fitted before installing nuts, bolts and washers. Tighten nuts.

(2) Set unit into cradle and align with ducting.

(3) Fit securing strap and secure T-bolt latch with nut.

(4) At outlet end of unit attach duct making sure that gasket is fitted before installing bolts, washers and nuts (detail A). Tighten nuts.

(5) Install clamp at inlet end as shown in detail B using new 'O' ring seal Pt. No. 69494-J-245.

(6) Install and secure electrical connection to unit.

(7) Install access panels 240 AR and 240 BR on forward fairing.

(8) Close C/B No. 211 on distribution panel 2D.



Ram/Main Fan - Removal/InstallationFigure 201



AMM21-00-26 7.0.0.0RAM/MAIN FAN SHUT-OFF VALVE - MAINTENANCE PRACTICES



A. Remove a shut-off valve.

(1) Isolate electrical supply by opening C/B No. 211 on distribution panel 2D.

(2) Remove access panel 240AR and 240BR on forward fairing.

(3) Disconnect electrical connection from unit.

(4) Unscrew flange clamp at outlet end of unit (detail A).

(5) Unscrew clamp at inlet end of unit (detail B).

(6) Remove unit.

B. Install a shut-off valve

(1) Align unit with main fan and air inlet, and ensure that arrow on unit is pointing in direction of flow.

(2) At outlet end of unit make attachment to ground fan as shown in detail A, using new 'O' ring seal Pt. No. Pt 69494-J-245.

(3) At inlet end of unit make attachment to plenum chamber as shown in detail B.

(4) Insert and secure electrical connection to unit.

(5) Install access panel 240AR and 240BR on forward fairing.




Ram/Main Fan Shut-off Valve - Removal/InstallationFigure 201



AMM21-00-31 8.0.0.0RECIRCULATION FAN - MAINTENANCE PRACTICES



A. Remove a re-circulation fan

(1) Isolate electrical supply by opening circuit breaker No. 208 on distribution panel 2D.

(2) Refer to 6-30-00, pb1. Remove panels 240AR, 240BR, 240AL, 240EL and 240CL to provide access to fan situated on aircraft centre line between stations 137 and 179.

(3) Remove cover from electrical connector box and disconnect cable from terminal block.

NOTE: Identify cable connections for subsequent re-connection.

(4) Remove six nuts, bolts and washers from each mounting bracket/duct flange.

(5) Remove unit from ducting.

(6) Remove and discard both flange gaskets.

B. Instal a re-circulation fan

(1) Instal unit in ducting/mounting brackets using new gaskets Part No. SD3-74-6131.

(2) Instal six bolts, washers and nuts on each flange.

(3) Torque tighten nuts. Refer to 20-09-06, pb1.

(4) Re-connect cable as noted during dis-assembly (para 1.A.). Replace cover.

(5) Replace access panels 240AR, 240BR, 240AL, 240EL, and 240CL.

(6) Close circuit breaker No. 208 on distribution panel 2D.



Recirculation Fan - Removal/InstallationFigure 201



AMM21-00-36 9.0.0.0RECIRCULATION/GROUND INTAKE SHUT-OFF VALVES - MAINTENANCE PRACTICES



A. Remove a recirculation or ground intake shut-off valve.

(1) Isolate electrical supply by opening circuit breaker No.208 on distribution panel 2D.

(2) Refer to 6-30-00, pb1. Remove panel 240AR, 240BR, 240AL, 240EL and 240CL to provide access to shut-off valves situated on aircraft centre line between stations 137 and 179.


(4) Release downstream clamp - detail A.

(5) Release upstream clamp as appropriate:-

(a) Recirculation shut-off valve - detail B.

(b) Ground intake shut-off valve - detail C.

(6) Remove unit and discard 'O' ring.

B. Instal a recirculation or ground intake shut-off valve.

(1) Insert new 'O' ring Part No. 69494 J-245 in shut-off valve recess.

(2) Align unit in ducting with arrow pointing in direction of flow.

(3) Secure valve clamps.

NOTE: Torque tighten downstream clamp to 70 lbs.in.

(4) Insert and tighten electrical connection.

(5) Replace access panels 240AR, 240BR, 240AL, 240EL and 240CL.




Recirculation/Ground Intake Shut-Off Valves - Removal/InstallationFigure 201



AMM21-00-41 10.0.0.0DUAL BY-PASS VALVE - MAINTENANCE PRACTICES



A. Remove a dual by-pass valve

(1) Isolate electrical supply by opening C/B No.211 on distribution panel 2D.

(2) Remove access panel 240CL on forward fairing.


(4) Make the following disconnections leaving ducts loosely in approximate installation positions to ease subsequent re-installation of dual by-pass valve.

(5) Disconnect at unit end (see detail A for typical attachment).

- Duct, pack by-pass valve 'IN'- Duct, pack by-pass valve 'OUT'- Duct, heat exchanger to turbine- Duct, turbine outlet

(6) Unscrew four bolts holding mounting channel to structure.

(7) Withdraw unit.

B. Install a by-pass valve

(1) Align unit mounting channel attachment holes with self-locking nuts in structure.

(2) Fit bolts and washers. Tighten bolts.

(3) Make the following ducting connections with reference to detail A using new 'O' ring seals Pt. No. 69494-J-137.

- Duct, turbine outlet- Duct, heat exchanger to turbine- Duct, pack by-pass valve 'OUT'- Duct, pack by-pass valve 'IN'

(4) Screw electrical connection to unit.

(5) Install access panel 240CL on forward fairing.




Dual By-Pass Valve - Removal/InstallationFigure 201



AMM21-00-46 11.0.0.0BY-PASS VALVE - MAINTENANCE PRACTICES



A. Remove a by-pass valve

(1) Isolate electrical supply by opening C/B No.90 on distribution panel 1D.

(2) Remove access panel 240CL on forward fairing.

(3) Disconnect electrical connection from unit.

(4) Make the following disconnections leaving ducts loosely in approximate installation positions to ease subsequent re-installation of single by-pass valve.

(5) Disconnect at unit end

(a) Duct, pack by-pass valve 'IN' (detail A)

(b) Duct, flight compartment air (detail B)

(6) Remove two nuts, bolts and washers attaching unit mounting bracket to structure.

(7) Withdraw unit.

B. Instal a by-pass valve

(1) Align unit mounting bracket attachment holes with holes in structure.

(2) Fit bolts, nuts and washers. Tighten nuts.

(3) Make the following ducting connections with reference to the appropriate details

(a) Duct, flight compartment air (detail B)

(b) Duct, pack by-pass valve 'IN' (detail A) using new cono seal Pt.No.51134-150A.

(4) Make electrical connection to unit.

(5) Instal access panel 240CL on forward fairing.

(6) Close C/B No.90 on distribution panel 1D.



By-Pass Valve - Removal/InstallationFigure 201



AMM21-00-51 12.0.0.0SPAR BOX HEAT PROTECTION SYSTEM - MAINTENANCE PRACTICES


A. Remove a thermostat assembly

(1) Open access panel 510ET (left) or 610ET (right) on upper surface of wing between front and rear spar and adjacent to wing rib Stn.68.8.


(3) Disconnect two leads attached to terminal block TB.91 (left) or TB.90 (right) terminals 1 and 2.

(4) Remove two screws and washers attaching thermostat and terminal block mounting tray to rib at Stn.68.8, and remove assembly from aircraft, retaining screws and washers.

B. Install a thermostat assembly

(1) Open access panel 510ET (left) or 610ET (right) adjacent to wing rib Stn.68.8.


(3) Attach thermostat and terminal block mounting tray to lipped channel member on rib at Stn.68.8 with two screws and washers, picking up anchor nuts on channel member.

(4) Re-connect leads to terminals 1 and 2 of terminal block TB.91 (left) or TB.90 (right).

(5) Close circuit breaker No. 196 on right distribution panel 2D.

(6) Close access panels 510ET (left) or 610ET (right).

2. Adjustment/Test

A. Function check a thermostat in situ.

Special tools and equipment:-

- Thermometer suitably calibrated to 300°F (150°C).- Hot air source or electrically heated muff

(1) Obtain access to thermostat assembly through access panels 510ET (left) or 610ET (right) on upper surface of wing between front and rear spar, adjacent to wing rib Stn.68.8


(3) Remove two screws and washers attaching thermostat and terminal block, mounting tray to rib at Stn.68.8, and retain.



(4) Remove assembly from aircraft with the electrical leads (extended) still attached to terminal block TB.91 (left) or TB.90 (right) and place on wing upper surface, using a suitable mat to insulate the wing surface from the heat source.

(5) Close circuit breaker No. 196.

(6) Apply heat and slowly raise temperature, with thermometer in close proximity to thermostat, noting that amber SPAR BOX OVERHEAT warning light on panel 9P in flight compartment illuminates when 225°F is recorded on thermometer, and is extinguished when heat is removed and temperature falls to 205°F.

(7) Open circuit breaker No. 196.

(8) Install assembly onto its mounting structure on rib Stn.68.8, ensuring that electrical leads are coiled and stowed securely to adjacent structure.


(10) Close access panels 510ET (left or 610ET (right).



AMM21-00-56 13.0.0.0CHECK VALVES (PT.NO. HTE4187) - MAINTENANCE PRACTICES

1. Adjustment/Test

A. Function check a valve

Special tools and equipment.

Compressed air source capable of 37 p.s.i.

(1) Close circuit breakers Nos.90 and 211 or respective distribution panel 1D and 2D.

(2) On AIR CONDITIONING PANEL 9P check that:-

(a) All indicator modules display 'off line'.

(b) All warning lights are extinguished.

(c) All switches and selectors are OFF or MANUAL.

(3) Refer to 6-30-00, pb1. Open access panel 240AL (zone 200).

(4) Disconnect pipe joint at stations 158.75 and 206.61 located over left fuselage side-wall (hand tight couplings).

(5) Release pipe clamps at stations 161.75, 179.8 and 193.10 and remove pipe section. Blank off forward pipe connection.

(6) Remove access panel 410AL (zone 400) on left and right engine nacelles.

(7) Disconnect flexible pipes at P2.5 and P3 bleed points on each engine. Blank off engine bleed orifices.

NOTE: The P2.5 bleed connection must be disconnected downstream of the aerofoil de-ice tapping.

(8) Select LEFT ENGINE and RIGHT ENGINE HA/SOVs on AIR CONDITIONING panel 9P to ON.

(9) Perform check valve tests using a dry, compressed air supply, making connections and blanking off ducts as detailed in the following tables for left and right engines. Test sequence No.1 (at either engine) signifies that the respective check valves are open by the emission of air from the common duct and test sequence No.2 signifies that the respective check valves are closed by a sustained pressure of 37 psi. Check valves are identified in schematic diagram. Refer to Figure 201.



LEFT ENGINE

RIGHT ENGINE

(10) Select LEFT ENGINE and RIGHT ENGINE HA/SOVs OFF.

(11) Re-connect P2.5 and P3 bleed pipes at each engine.

(12) Replace access panels 410AL on each engine nacelle.

(13) Re-connect pipe in fuselage fairing and tighten clamps.

NOTE: Couplings should be tightened by hand.

(14) Replace access panel 240AL on fairing.

TestSequence

BlankOff

ApplyPressurised Air

AirDischarge

Air Pressure

Check ValveFunction

1 P3 P2.5 PipeConnection

At commonline duct

1L + 2L - Open

2 Common LineDuct

P3 PipeConnection

Maintainedat 37 p.s.i.

1L + 2R - Closed

TestSequence

BlankOff

ApplyPressurised Air

AirDischarge

AirPressure

Check ValveFunction

1 P3 P2.5 PipeConnection

At commonline duct

1R + 2R-Open

2 Common Line Duct

P3 Pipe Connection Maintainedat 37 p.s.i.

1R + 2L-Closed



Check Valve - Function TestFigure 201



AMM21-00-61 14.0.0.0L.P. SWITCHES - MAINTENANCE PRACTICES

1. Adjustment/Test

A. Perform operational check on left and right LP switches.

(1) Inhibit centre duct LP switch as follows:-

(a) Open circuit breaker No. 196 on distribution panel 2D.

(b) Refer to 6-30-00, pb1. Remove access panels 240AL and 240EL on fuselage roof fairing

(c) Disconnect wiring from centre duct LP switch (3HE13). Refer to 21-00-66, Figure 201

(2) Close circuit breakers No. 90 on distribution panel 1D and circuit breakers Nos 196 and 211 on distribution panel 2D.

(3) Select LEFT ENGINE HA/SOV ON and check that DUCT LOW PRESSURE warning light (panel 9P) illuminates.

(4) Refer to 71-00-00, pb1. Start left engine and check that DUCT LOW PRESSURE light is extinguished.

(5) Stop engine and check that DUCT LOW PRESSURE light illuminates during engine rundown.

(6) Repeat paras 1.A.(3) thru 1.A.(5) reading right for left.

(7) Re-connect centre duct LP switch wiring and replace access panels.

B. Perform operational check on centre duct LP switch.

(1) Inhibit left and right LP switches as follows:-

(a) Open circuit breakers No. 196 and 211 (panel 2D).

(b) Refer to 6-30-00, pb1. Lower left engine cowl 420BB and disconnect wiring from left LP switch (1HE13) situated aft of engine rear firewall.

(2) Close circuit breakers Nos 90 and 196 on respective distribution panels 1D and 2D.

(3) Repeat paras 1.A.(3) thru 1.A.(5).

(4) Re-connect left LP switch wiring and close engine cowl.



AMM21-00-66 15.0.0.0H.P. SWITCH - MAINTENANCE PRACTICES

1. Adjustment/Test

A. Function check the switch


(1) Refer to 6-30-00, pb1. Remove access panel 240CL and locate the switch.

(2) Disconnect signalling input pipe at tee junction and blank off.

(3) Fit a suitable adapter to tee junction and connect a dry air supply regulated to a pressure of 50 p.s.i.

(4) Provide electrical power. Refer to 12-09-03, pb301.


(6) Apply pressure and slowly raise until amber OVER PRESSURE warning light on panel 9P illuminates, when the pressure reaches 35 ± 1 p.s.i.

(7) Reduce pressure slowly, noting that the warning light extinguishes when the pressure falls to not less than 29 p.s.i.

(8) Reduce pressure to zero and disconnect air supply and adapter.

(9) Remove blank from signal input pipe and re-connect pipe to tee junction.

(10) Replace access panel 240CL.

(11) Open circuit breaker No.196, and return aircraft to the unpowered state.



Location of H.P. SwitchFigure 201



AMM21-00-71 16.0.0.0DUCT/FLIGHT COMPARTMENT /PASSENGER COMPARTMENT OVERHEAT SWITCHES - MAINTENANCE PRACTICES


Refer to Figure 201

A. Remove a switch

(1) Isolate electrical supply by opening circuit breaker No. 196 on distribution panel 2D.

(2) Obtain access to appropriate switch (HE-18 - Flight Compt., HE17 - passenger compt., HE16 - duct) by removing respective access panels 240 AR, 240 AL and 240 BL.

(3) Remove local insulation (lagging).

(4) Cut lockwire and unscrew electrical connection.

(5) Unscrew and remove switch from duct; blank off duct connection.

B. Install a switch

NOTE: Prior to installation of a new switch perform function check detailed in para 2.A.

(1) Isolate electrical supply (para 1.A.(1)).

(2) Ensure that switch part number is appropriate to intended siting.

(3) Fit new 'O' ring seal Pt. No. MS28778-5 to flight and passenger compartment switch bodies.

(4) Install and fully tighten the switch in the duct.

(5) Secure electrical connection and wirelock.

(6) Re-install lagging.

(7) Replace access panels 240AR, 240AL and 240BL.



Overheat switchesFigure 201



2. Adjustment/Test

A. Function test switches


Thermometer (suitably calibrated from 32°F to 570°F (0-300°C)).

Hot air source or electrically heated muff.

(1) Identify and reconnect electrical connector/s to switch/es.

(2) Refer to 12-09-03, pb301. Provide electrical power and close circuit breaker No. 196 on distribution panel 2D.

(3) Place switch/es on fuselage surface (upper), using suitable mats to insulate the surface from heat source.

(4) Apply heat to the switch using a heating muff or hot air source, increasing the temperature slowly with the thermometer in close proximity to the probe. With reference to the following table, check that the relevant OVERHEAT light on panel 9P and the BLEED air caption on the centralised warning panel 1P illuminate when the probe temperature rises to within the switching tolerance and extinguishes when the heat source is removed and the temperature 'falls' to the specified minimum.

SUPPLY DUCT SWITCH PT.NO. RISING TEMP.(lights on)

FALLING TEMP.

Flight Comp. 750665/2 235° F +10° F 230° F

Passenger Comp 750665/1 185° F +10° F 180° F

Primary Heatexchanger inlet

B01A218013A 525° F +9° F 450° F

- 0

- 0

-9°



AMM21-00-76 17.0.0.0HOT AIR SHUT-OFF VALVES (PT NO HTE9215) - MAINTENANCE PRACTICES



A. Remove a HA/SOV unit

(1) Refer to 12-09-03, pb301. Open circuit breakers No.90 and 211 on distribution panels 1D and 2D for left and right engines respectively and tag as detailed in general precautions.

(2) Refer to 6-30-00, pb1. Remove and retain access panel 410AL from engine cowling. Locate HA/SOV (idented HE5) situated on left side of engine, aft of rear fireshield.

(3) Unscrew electrical connector.

(4) Remove the insulation muff from around the valve body to expose the duct valve sealing clamps.

(5) Release the sealing clamps and remove the valve from the duct.

(6) Discard both gaskets.

B. Instal a HA/SOV unit

(1) Fit new gaskets Pt Nos SD3-74-0060/A and SD3-74-0060/C, to flanges of HA/SOV.

(2) Align the unit in the ducting with the electrical connection to the top and fit sealing clamps.

(3) With the valve correctly positioned, initially torque clamp fixing screws to 25 lb in. Tap around clamp to ensure correct bedding and finally torque to 35 lb in.

(4) Fit insulation muff around valve body.


(6) Replace access panel 410AL on engine cowling.

(7) Perform function check detailed in para 2.A.

2. Adjustment/Test

A. Function check HA/SOV units.

(1) Close circuit breakers Nos 90 and 211 on respective distribution panels 1D and 2D.

(2) Depress LEFT ENGINE HA/SOV switch to ON position and check that integral line indicator displays 'on line'.



(3) Release LEFT ENGINE HA/SOV switch to OFF position and check that indicator displays 'off line'.

(4) Repeat (3) and (4) reading right for left.



Hot Air Shut-Off Valve - Removal/InstallaionFigure 201



AMM21-00-81 18.0.0.0TEMPERATURE CONTROL VALVE PT NO 750655-4 MAINTENANCE PRACTICES



A. Remove a TCV unit

(1) Refer to 12-09-03, pb301. Open circuit breakers No 90 and 211 on distribution panels 1D and 2D for left and right engines respectively and tag as detailed in general precautions.

(2) Refer to 6-30-00, pb1. Remove and retain access panel 410AL from engine cowling. Locate TCV (idented HE1) situated on left side of engine, aft of rear fireshield.

(3) Unscrew electrical connector.

(4) Disconnect pipe unions P3 and P4.

(5) Remove the insulation muff from around the valve body to expose the duct valve sealing flanges.

(6) Unscrew flange securing bolts (8) and remove the unit.

(7) Discard both gaskets.

B. Instal a TCV unit

(1) Fit new gaskets Pt No AN123037 (2) to flanges of TCV.

(2) Align the unit in the ducting and insert the fixing bolts.

(3) Torque tighten fixing bolts. Refer to 20-09-06, pb1.

(4) Connect pipe unions P3 and P4 and torque tighten. Refer to 20-09-04, pb1.

(5) Fit insulation muff around valve junction.


(7) Replace access panel 410AL on engine cowling.

(8) Close circuit breakers No 90 and 211 on respective distribution panels 1D and 2D.



Temperature Control Valve - Removal/InstallationFigure 201



AMM21-00-86 19.0.0.0PRE-COOLER OVERHEAT SWITCH - MAINTENANCE PRACTICES


A. Remove a switch

(1) Check that circuit breaker No. 196 on right distribution panel 2D is open.

(2) Obtain access to switch by removing access panel 240CL (zone 200).

(3) Disconnect electrical connection to switch.

(4) Unscrew overheat switch (HE. 16) from duct, and blank off exposed threaded duct connection.

B. Install a switch

(1) Check that circuit breaker No. 196 on right distribution panel 2D is open.


(3) Remove blank from duct connection.

(4) Insert thermal switch sensor probe into duct, having positioned the thermometer washer into the attachment nut prior to installation.

(5) Tighten the attachment nut, using only the flats on the body to hold the pre-cooler overheat switch when tightening.

(6) Re-connect electrical connection to switch.

(7) Refit access panel 240CL.

2. Adjustment/Test

A. Function check the switch in situ.


Thermometer (suitably calibrated to 280° C).

Hot air source or electrically heated muff.



(3) Unscrew overheat switch from duct, and blank off exposed threaded duct connection.



(4) Remove overheat switch from aircraft, leaving electrical connection still attached to the switch, and place on fuselage upper surface using a suitable mat to insulate the fuselage surface from the heat source.


(6) Apply heat and slowly raise temperature with the thermometer in close proximity to the switch probe, noting that the amber OVERHEAT warning light on panel 9P in flight compartment illuminates when 274° C ± 5° C is recorded on the thermometer and extinguishes when heat is removed and the temperature falls to between 15° C and 40° C below the previously recorded temperature.

(7) Open circuit breaker No. 196.

(8) Remove blank from duct connection and install switch into duct, ensuring that the extended electrical leads are coiled and stowed securely to adjacent structure.


(10) Close access panel 240CL.



AMM21-50-00 20.0.0.0AIRCRAFT COOLING SYSTEMS - GENERAL

1. General

Freon cooling systems are provided for the flight compartment and cabin of aircraft to post-mod 8121, 8122 & 8309 standard. Refer to 21-52-00, pb1.

The flight compartment is also equipped with two fans, one for each pilot. Refer to 21-51-00, pb1.



AMM21-51-00 21.0.0.01ST & 2ND PILOTS FANS - DESCRIPTION & OPERATION

1. Description

The 1st and 2nd pilots are each provided with a fan to provide additional air movement in the flight compartment. The fans, left and right, are attached to the coaming at station 37.5 and are individually controlled by an adjacent ON/OFF switch.

2. Power Supplies

Power supplies for 1st and 2nd pilots fans are respectively taken from the left and right 28V d.c. general services busbars via 5 amp circuit breakers Nos 75 and 225 on distribution panels 1D and 2D.



AMM21-51-00 22.0.0.01ST & 2ND PILOTS FANS - MAINTENANCE PRACTICES

1. Adjustment/Test

A. Function/Test

(1) Function check.

(a) Refer to 12-09-03, pb301. Provide electrical power.

(b) Close circuit breaker No. 75 on distribution panel 1D.

(c) Select control switch for left fan ON and check that left fan operates satisfactorily.

(d) Select control switch OFF and ensure that fan stops.

(e) Repeat operations (1) to (4) reading right for left and circuit breaker No. 225 on distribution panel 2D for circuit breaker No. 75 on distribution panel 1D.

(f) Switch off electrical supply.



AMM21-52-00 23.0.0.0FREON COOLING - DESCRIPTION & OPERATION (POST MOD 8121, 8122 & 8309)

1. Description

A. General

Refer to Figure 1.

The Freon cooling system consists of two sub-systems; a forward system which provides cooling of the forward end of the passenger cabin and flight deck and an aft system which provides cooling of the rear of passenger cabin.

The Freon cooling system is an ambient air recirculatory system. The refrigerant, in the form of a hot gas at high pressure, is passed to the condenser which is cooled by a fan. The resultant liquid refrigerant then passes to an evaporator via an expansion valve.

The cabin air, circulated through the evaporator by a fan, is discharged into the cabin at a very low temperature due to the heat transfer from the cabin air causing evaporation of the liquid refrigerant. During the cooling mode water is extracted from the air, thus reducing humidity.

The system is controlled by two panels, one operated by the second pilot and the other operated by the flight attendant. The second pilot's panel, idented HEA5, is located below panels 9P and 11P. Refer to Figure 2. The flight attendants panel, idented HEA6 is located between frames 488.5 and 508. Refer to Figure 3.

B. Compressor - Condenser Module

Two compressor-condenser units (Pt. No. 1250400-20) are installed in the top fairing between stations 146.2 and 158.8, one serving the flight deck and the forward end of the passenger cabin, whilst the other serves the aft end of the passenger cabin. The module consists of an electric-motor, a compressor, a condenser coil, a receiver-dryer unit, a low pressure switch and a high pressure switch.

The unit compresses the refrigerant gas to a hot, high pressure gas and then passes it through a condenser coil where it is condensed to a warm liquid under constant pressure. The warm liquid is then routed to the receiver dryer unit where the liquid and any remaining gas are separated.

C. Evaporator and Blower Units

NOTE: The units are installed within the cabin and flight deck.

The system consists of four evaporator units:-

- Left Hand Evaporator Module (Pt. No. 1250290-8)- Right Hand Evaporator Module (Pt. No. 1250290-9)- Aft Evaporator Module (Pt. No. 1250390-5)- Flight Compartment Evaporator module (Pt. No. 1250200-25).



Block Diagram of Forward and Aft SystemsFigure 1



System Component Location and Pilots Control PaneFigure 2



The left and right evaporators modules are similar and consist of a coil assembly and a blower assembly which are respectively located at frame stations 104 and 74

The flight deck module and aft module are similar in respect that they contain their evaporator and blower units as one assembly. The flight deck module is located at frame station 37.5 whilst the aft unit is located in the rear cabin locker module forward of frame station 475.

2. Operation

A 28V dc supply is derived from the LEFT and RIGHT SHEDDING busbars and either a combination of LEFT MAIN busbar and the GROUND SERVICES busbar (in flight) or purely the GROUND SERVICES busbar (on ground).

Power is derived through the following circuit breakers CB151 on panel 2D, CB424 on panel 5D, CB454 on panel 6D, and circuit breakers A, B and C on panel HEA9.

Contactors D and E on panel HEA2 are installed to prevent electrical interlocking between the LEFT MAIN busbar and the GROUND SERVICES busbar while on the ground.

The FREON COOLING MASTER switch, located on panel HEAS, controls the entire system. Information that the system is functional is given to the flight attendant by the illumination of the ACTIVE lamp.on panel HEA6.

Selection of the OFF/FAN ONLY/ON switches to ON and the FAN ON/OFF switch to FAN ON will provide cooling with the compressors operating. Should it be necessary for a compressor to be shut down, air movement may still be provided by the selection of the appropriate switch to FAN ONLY, operating the evaporator blower only. However, if the forward compressor is shut down, selection of the associated switch to FAN ONLY will provide air movement for the flight deck only. It is necessary for the flight attendant to select the OFF/FAN ON switch to FAN ON to provide air movement for the forward end of the passenger cabin.

Evaporator fan speed is controlled by the selection of the appropriate switch to the 'HI' or 'LO' position.

Indication that the compressors are operating is given by the illumination of the appropriate lamps on the second pilots panel and on the flight attendants panel. Compressor operation will be inhibited during an engine start or should the pressure drop to below 32 PSI (possible leak) or rise to above 300 PSI (possible blockage).

A low pressure warning is given on the second pilot's panel, should low pressure switch HEA11 be tripped. This indicates a leak in the forward cabin and flight deck system piping or components thus protecting the flight crew for an accumulating unacceptable contamination level in the flight compartment.

The duration of operation of the fore and aft compressors is recorded on their respective hour meters, which are located on the right hand side of the aircraft between stations 146 and 175.

NOTE: This is duration of operation of the Freon cooling system and not flight hours.



Circuit Breaker Panel and Flight Attendants Control PanelFigure 3



AMM21-52-00 24.0.0.0FREON COOLNG - TROUBLESHOOTNG

1. General

A list of symptoms, probable causes and possible solutions are given in the table which follows:

Table 101

SYMPTON PROBABLECAUSE POSSBLESOLUTON

No system power External power source not connected

Connect external power supply

Electrical Master switch is off Select the ELECTRCAL MASTER switch to the appropriate setting

Power is on, but system will not operate

Circut breaker is open Close the circuit breakerCircuit breaker failed Replace the circuit breakerAir conditioner mode switch failed Replace the mode switchHigh pressure switch failed Replace the switchLow pressure switch failed Replace the switchPower contactor failed Replace the power contactorDrive motor failed Replace the drive motorVented system Chech pressure, evaluate, and

chargeLow ambient temperature Normal cut out functionDrive motor fuse is blown Replace the fuse

System operates but is not cooling

Low refrigeration charge Charge the systemOver charged system cut out Bleed the systemCompressor failed Replade the compressorDrive motor failed Replace the motorDrive belt broke Replace the beltExpansion valve(s) failed Replace the valveEvaporator blower switch failed Replace the switchEvaporator blower(s) motor failed Replace the motor(s)Evaporator blower(s) failed Replace the blower(s)Evaporator blower(s) circuitbreaker is open

Close the circuit breaker

Evaporator module(s) air inlet is blocked

Remove any debris

Expansion valve inlet filter is blocked Remove any debris



Excessive moisture in the system Replace the receiver-dryer assembly

Noisy evaporator module Blower wheel is loose Replace the blower wheelBlower wheel hitting scroll Align the blower wheelDefective blower motor bearing Replace the motorLoose mounting bracket(s) Tighten the bracket(s)Air inlet is blocked Remove any debris

Noisy compressor motor assembly

Drive belt is loose Re-tension the beltDrive belt is hitting the cover Re-align the belt and adjust the

bracketsMotor fan hitting the shroud Adjust the motor fanDefective compressor Replace the compressorDefective drive Replace the drive belt beltLoose pulley(s) Tighten or replace the pulley(s)Loose mounting hardware Check and tighten the hardwareLoose hose assembly Tighten the hose couplingsLoose fan blade Replace the fan blade

Evaporator fan speed does not work on low speed (high speed works)

Failed switch Replace the switchFailed resistor Replace the resistor

Compressor Condenser assembly does not operate

Circuit breaker is open Close the circuit breakerCircuit breaker failed Replace the circuit breakerHigh pressure switch failed Replace the high-pressure switchPower contactor failed Replace the power contactorDrive motor failed Replace the drive motorLow-pressure switch failed Replace the low pressure switchLow ambient temperature Normal cut outLow refrigerant charge Re-charge the system

NoAirFlow in evaporator module(s)

Circuit breaker is open Close the circuit breakerCircuit breaker failed Replace the circuit breakerModeSwitch failed Replace the mode switchFan speed switch failed Replace the fan mode switchSeized motor(s) Replace the motor(s)Blower wheel failed Replace the blower wheelAir inlet is blocked Remove any debrisAir outlet is blocked Remove any debris




Evaporator module coil is freezing

No air flow Switch on the fanExpansion valve failed Replace the expansion valveExpansion valve is blocked Remove any debrisExpansion valve setting is too low Re-set to obtain 26-30 psig

suction pressHigh pressure switch is cycling

System is over charged Vent as requiredCondenser coil inlet air is extremly hot

No fix necessary, normal condition

Condenser coil inlet air is blocked Remove any debrisDischarge line is blocked Remove any debrisDischarge line is kinked Straighten the hose

Cockpit fan assembly is not operating

Forward blower is off Switch on the forward blowerFan circuit breaker is open Close the circuit breakerFan circuit breakerfailed Replace the circuit breakerCockpit fan is off Switch on the fanCockpit fan switch failed Replace the fan switchFan assembly failed Replace the fan assembly




AMM21-52-00 25.0.0.0FREON SYSTEM - MAINTENANCE PRACTICES

1. Adjustment/Test

A. Function check of the shedding relays

There are two methods for performing this check, Engines shut down and Engines running

(1) Engine shut down

NOTE: Do not allow the Freon System to operate for longer than required when the compressor motor is being powered from battery power.

(a) Select the ELECTRICAL MASTER switch (4P) to INTERAL and select both the LEFT and RIGHT MAIN BATTERY ON/OFF switches (4P) to ON.

(b) Trip circuit breaker CB 454.

(c) Ensure circuit breakers CB5, CB155, CB423, CB424, CB452, HEA9-A (125A CB on Left Main Busbar) and HEA9-C (125A CB on Ground Services Busbar) are set.

(d) Ensure that both the LEFT and RIGHT LOAD SHED switches (4P) are set to NORMAL.

(e) On the Pilots Freon Air-conditioning control panel select the Freon Master ON/OFF switch to ON.

(f) On the flight Attendants Freon Control panel select the ON/FAN ONLY/OFF switch to ON.

(g) Ensure the Freon Air Conditioning does not operate.

(h) Select the LEFT LOAD SHEDDING switch (4P) to EMGY, ensure the Freon Air Conditioning is not operating.

(i) Select the RIGHT LOAD SHEDDING switch (4P) to EMGY. Ensure the aft Freon Air Conditioning is operating. Select this switch to NORMAL and ensure the air conditioning is now off.

(j) Select the ON/FAN ONLY/OFF switch on the flight attendants control panel to OFF and select the LEFT LOAD SELEDDING switch (4P) to NORMAL.

(k) Trip circuit breaker CB424 and reset circuit breaker CB454.

(l) Select the RIGHT LOAD SHEDDING switch (4P) to EMGY. Ensure the Freon System is not operating.

(m) Select the LEFT LOAD SHEDDING switch (4P) to EMGY.

(n) On the pilots Freon Control Panel select the ON/FAN ONLY/OFF switch to ON.



(o) Ensure the Freon Air Conditioning System in the flight compartment is operating. Select this switch to NORMAL and ensure the air conditioning is now off.

(p) Select the ON/FAN ONLY/OFF switch on the Flight Compartment Freon Control Panel to OFF and select both LOAD SHEDDING switches (4P) to NORMAL.

(2) Engine running

(a) Ensure circuit breakers CB423, CB424, HEA9-A (125A CB on Left Main Busbar), HEA9-C (125A CB on Ground Services Busbar), CB452 and CB454 are set.

(b) Ensure both engines are running and both generators are on-line.

(c) Energize the left load shedding busbar by resetting circuit breaker CB5 and re-selecting the left load shedding switch to EMGY.

(d) On the pilots Freon Air Conditioning control panel set the ON/OFF switch to ON and the ON/FAN ONLY/OFF switch to FAN ONLY.

(e) Ensure that the Pilots air conditioning is operating "Fan Only".

(f) Set the right generator TRIP/RESET switch (4P) to TRIP. Ensure that the right generator is off-line.

(g) Ensure the Pilots 'Freon fan' is now off.

(h) Set the right generator ON/OFF/COUPLE switch (4P) to COUPLE.

(i) Ensure the Pilots 'Freon fan' remains off.

(j) Set the right generator ON/OFF/COUPLE switch (4P) to ON and the right generator TRIP/RESET switch (4P) to RESET.

(k) Ensure that the right generator is on line and the Pilots Freon fan is operating.

(l) Set the pilots ON/FAN ONLY/OFF switch to OFF. Ensure the Pilots Freon fan is off.

(m) On the flight Attendants Freon Control Panel set the ON/FAN ONLY/OFF switch to FAN ONLY.

(n) Ensure that the aft fan is operating 'fan only'.

(o) Set the left generator TRIP/RESET switch (4P) to TRIP. Ensure that the left generator is off-line.

(p) Ensure that the aft fan is now off.

(q) Set the left generator ON/OFF/COUPLE switch (4P) to COUPLE.

(r) Ensure that the aft fan remains off.



(s) Set the left generator ON/OFF/COUPLE switch (4P) to ON and the right generator TRIP/RESET switch (4P) to RESET.

(t) Ensure that the left generator is on line and the aft fan is operating.

(u) Set the ON/FAN ONLY/OFF switch on the flight attendants control panel to OFF.

(v) Ensure the aft fan is off.

B. Function check of the low pressure indication relay

(1) Reset circuit breakers HEA9-C (125A CB on Ground Services busbar), CB452 and CB453.

(2) Connect a Ground Power Unit to the aircraft and select the ELECTRICAL MASTER switch (4P) to EXTERNAL.

(3) On the pilots Freon Control Panel select both the ON/OFF and ON/FAN ONLY/OFF switch to ON.

(4) Ensure the Forward Freon Air Conditioning system is operating and the low pressure warning light on the Pilots Freon Control Panel is extinguished.

(5) Select the Pilots Freon ON/OFF and ON/FAN ONLY/OFF switches to OFF. Render the aircraft electrically safe. Refer to 12-09-03, pb301.

(6) On TB209 (Frame 146-175 RHS) Pin 7, disconnect only the cable leading to HEA 11 Pin B Insulate the lug.

(7) Ensure the remaining cables to Pin 7 are connected.

(8) Reconnect the Ground Power Unit.

(9) On the pilots Freon Control Panel select both the ON/OFF and ON/FAN ONLY/OFF switches to ON.

(10) Ensure the Forward Freon Air Conditioning system is operating and the low pressure warning light is lit.

(11) Select the Pilots Freon ON/OFF and ON/FAN ONLY/OFF switches to OFF.

(12) Render the aircraft electrically safe. Refer to 12-09-03, pb301.

(13) Reconnect the cable disconnected at step (6).

(14) Reconnect the Group Power Unit and select the ON/OFF and ON/FAN ONLY/OFF switches on the Pilots Freon Control Panel to ON.

(15) Ensure the forward Freon Air Conditioning system is operating and the Low Pressure Warning Light on the Pilots Freon Control Panel is extinguished.



(16) Select the ON/OFF and ON/FAN ONLY/OFF switches on the Pilots Freon Control Panel to OFF.

C. Function check of the evaporator system thermostats

Each thermostat should be removed and placed in a calibrated oven. The required test values are 250 ± 10 °F Dropout and 220 ± 10 °F Pickup.

D. Functional check of the low and high pressure switches

Each compressor/condenser assembly has a low pressure and high pressure switch which is wired in series with the compressor motor controlling contactor.

These switches are normally closed and operate as follows:

(1) High Pressure Switch Pt. No. 1250168-3 opens on pressure rise at 300 ± 20 psig and resets at 140 ± 20 psig as the pressure falls.

(2) Low Pressure Switch Pt. No. 1250154 closes on pressure rise at 30 ± 5 psig and opens at 15 ± 5 psig as the pressure falls.

As switches must be removed for testing, the Freon R-12 Refrigerant must be evacuated/recovered.

Removed switches are to be bench tested to show agreement with the above pressures. Any switch not meeting above requirements are to be discarded.

NOTE: Enviro Systems Inc. recommend the use of dry nitrogen to test pressure switches. Alternatively, dry compressed air can be used if nitrogen is unavailable.

Enviro Systems also recommend replacing the Receiver/Dryer when the system is opened for maintenance.

Each Flight Deck evaporator assembly has a low pressure switch, utilised to provide a low pressure warning in the Flight Deck, via an indication relay. This switch (1250247) is normally closed and operates in an identical manner to Low Pressure Switch 1250154.

NOTE: The bench testing for switch Pt. No. 1250247 is identical to bench testing for switch Pt. No. 1250154.

E. Function check of the cabin fan heater thermostats

(1) Connect a Ground Power Unit to the aircraft and select the ELECTRICAL MASTER switch (4P) to EXTERNAL.

(2) Select the Cabin Fan Heating MASTER ON/OFF switch on the Flight Compartment Control Panel to ON.

(3) Select both the HI/LO/OFF switches on the Flight Attendants Control Panel to HI.



(4) Allow the heater output to stabilise for approximately 10 minutes.

NOTE: The thermostats are designed to drop out at 93 °C and to pick up at 82 °C. Their correct operation can be confirmed by observing the heater elements through the front grill of the heater and ensuring that they cycle from ON to OFF periodically (ie from a warm red glow to OFF). The frequency of this cycle will depend on the ambient temperature.

If this test is carried out in extremely low temperatures, it may be necessary to partially restrict airflow to allow the heater elements to reach the thermostat drop-out temperature (93 °C).

(5) Select both the HI/LO/OFF switches on the Flight Attendants Control Panel to OFF.

(6) Select the MASTER ON/OFF switch on the Flight Compartment Control Panel to OFF.



AMM21-52-00 26.0.0.0FREON COOLING - SERVICING

1. Servicing

A. Evacuation Procedure

WARNING: REFRIGERANT IS EXTREMELY COLD AND MAY CAUSE BURNS. HAND, EYE AND MOUTH PROTECTION SHOULD BE WORN AT ALL TIMES.

CAUTION: USE REFRIGERANT (R-12) ONLY.

(1) Refer to 12-09-03, pb301. Render the aircraft electrically safe.

(2) Remove the condenser - compressor service access door located in the roof fairing.

(3) Disconnect the condenser hot air exhaust ducts.

(4) If necessary, remove the entire roof fairing.

(5) Remove the service port caps on the compressor.

(6) Connect the refrigerant charging manifold.

CAUTION: THE HIGH PRESSURE HOSE (RED) MUST BE CONNECTED TO THE PORT MARKED 'D' AND THE LOW PRESSURE HOSE (BLUE) MUST BE CONNECTED TO THE PORT MARKED 'S'.

(7) Ensure that all manifold valves are off.

(8) Connect the manifold-charging hose to the vacuum pump.

(9) Switch on the pump.

(10) Open both valves on the manifold assembly and observe the gauges.

NOTE: The blue low-pressure gauge will indicate a vacuum on the lower range of the pressure gauge.

(11) Evacuate the system for 20 minutes.

NOTE: System vacuum should reach 635 mm - 686 mm (25 - 27in)

(12) Close the manifold valves.

(13) Shut off the vacuum pump.

(14) Remove the service hose and connect it to the refrigerant can shut off valve on a new can.

NOTE: The recommeded can size is 0.88 lbs (14 oz).



(15) Open the can shut off valve.

(16) Loosen the manifold service fitting slightly to vent the hose.

(17) Tighten the hose fitting.

(18) Open both manifold valves and allow 7 oz of refrigerant to enter the system.

(19) Close both manifold valves.

(20) Close the refrigerant can shut off valve.

(21) Disconnect the service hose.

(22) Slowly open both manifold valves and slowly vent the system to 2 - 5 psig.

CAUTION: VENTING THE SYSTEM RAPIDLY WILL CAUSE THE REFRIGERANT OIL TO VENT OVERBOARD.

(23) When the system reaches 2 - 5 psig, close both manifold valves.

(24) Connect the manifold service hose to the vacuum pump.

(25) Evacuate for at least 15 minutes.

(26) Close both manifold valves and shut off the vacuum pump.

NOTE: The system vacuum must remain steady for 5 mins. Excessive water and or air in the system will cause pressure to rise.

(27) Disconnect manifold service hose.

NOTE: The system is now ready for refrigerant charging.

B. Charging Procedure

WARNING: HAND AND EYE PROTECTION MUST BE WORN DURING THIS PROCEDURE.


(2) Ensure the system is evacuated - refer to para 1.

(3) Connect the manifold charging hose to a refrigerant can shut off valve.

(4) Open the valve.

(5) Loosen the hose fitting at the manifold and vent the hose.

(6) Open both manifold valves and allow 14 oz of refrigerant to enter the system.



(7) Close both manifold valves and the can shut off valve.

(8) Disconnect the service valve from the refrigerant can.

(9) Repeat (3) thru (8) until tbe system pressure has stabilized at approximately 50 psig.

NOTE: It may be necessary to feed 28 to 42 oz of refrigerant into the system until ressure stabilizes.

If the internal pressure is not equal to or greater than 50 psig, the low pressure switch will not close and the drive motor power contactor will not operate.

(10) Refer to 12-09-03, pb301. Energize the Left and Right Shedding Busbars, the Left Main Busbar and the Ground Services Busbar.

(11) Select the evaporator blower speed switch to the HI position.

(12) Select the appropriate ON/FAN ONLY/OFF switch to ON.

(13) During operation, note the system discharge and suction pressure valves.

(14) Observe the condition of the refrigerant in the receiver dryer sight glass.

NOTE: Excessive bubbles in the sight glass indicate a low refrigerant level.

(15) Connect a new can of refrigerant to the charging hose and open the can shut off valve.

(16) Slowly open the blue suction mainfold valve and allow the pressure to increase to 60 - 70 psig while the refrigerant enters the compressor.

NOTE: As the refrigerant enters the compressor a slight increase in discharge pressure will be noted (2 - 5 psig) an the compressor speed will slow slightly.

(17) Continue to add refrigerant until the sight glass has only a 'moderate' amount of bubbles.

(18) Close the blue suction manifold valve and let the system operate for 5 - 10 minutes.

(19) Observe the sight glass. If the sight glass is not totally clear, open the suction manifold valve and add a small quantity of refrigerant until 98% of the bubbles disappear.

NOTE: When charging in hot ambient conditions (95° F 105° F), occasional bubbles are desired.

(20) Close the manifold valve and let the system stabilize.

NOTE: It is necessary to let the system stabilize because the expansion valves attempt to stabilize to the preset suction pressure value.



CAUTION: DO NOT OVERCHARGE THE SYSTEM.

The following charges are the maximums:-

FORWARD SYSTEM CHARGE: 3.1 lb (3.5 cans)

AFT SYSTEM CHARGE : 4.4 lb (5 cans)

(21) With the system fully charged and operating, observe the suction and discharge valves.

NOTE: Typical pressures at various ambient temperatures with hot passenger and crew compartments are shown below:

Table 301

(22) Allow the system to operate for 10 minutes.

(23) Switch off the power.

NOTE: When power is removed, both suction and discharge pressures will start equalizing. The pressures should be equal after 60 - 90 secs.

(24) Cover both compressor service valves with a shop towel and quickly remove both the high and low pressure hoses.

OUTSIDE AIR TEMPERATURE

SUCTIONPRESSURE (PSIG)

DISCHARGE PRESSURE (PSIG)

80°F 24 + - 2 195 + - 1095°F 26 215

103°F 28 230



AMM21-52-00 27.0.0.0FREON COOLING - ADJUSTMENT/TEST

1. Adjustment/Test

A. Test with ground power supply

(1) Ensure that all the air-conditioning control switches on both the flight compartment (HEA5) and flight attendants control panels are set to OFF.

(2) Select the START MASTER on panel 4P to NORMAL.

(3) Select the ELECTRICAL MASTER switch on panel 4P to OFF.

(4) Refer to 12-09-03, pb301. Connect an external power supply to the aircraft.

(5) Ensure the following circuit breakers have been closed.

(6) Select the FREON COOLING MASTER-ON/OFF switch on the FLIGHT CONPARTNENT CONTROL PANEL to OFF.

(7) Ensure that the 'ACTIVE' indicator on the FLIGHT ATTENDANTS CONTROL PANEL is not lit.

(8) Select the FREON COOLING MASTER-ON/OFF to ON.

(9) Ensure that the 'ACTIVE' indicator is lit.

(10) Select the ELECTRICAL MASTER switch to EXTERNAL and ensure the indicator remains lit.

(11) Select the ELECTRICAL MASTER switch to OFF.

(12) On the FLIGHT COMPARTNENT CONTROL PANEL, select the ON/FAN ONLY/OFF switch to FAN ONLY and the appropriate HI/LO switch to LO.

(13) Ensure that the fan in the flight deck is operating at low power.

Circuit Breaker Location

423 5D424 5D452 6D453 6D454 6DA HEA9B HEA9C HEA9



(14) Select the HI/LO switch on the FLIGHT COMPARTNENT CONTROL PANEL to HI.

(15) Ensure that the fan on the flight deck is operating at high power.

(16) Select the ON/FAN ONLY/OFF switch on the FLIGHT COMPARTMENT CONTROL PANEL to ON.

(17) Ensure that the 'COMPRESSOR' lamp on the FLIGHT COMPARTMENT CONTROL PANEL is lit.

(18) Ensure that the 'LOW PRESSURE' indicator on the FLIGHT COMPARTMENT CONTROL PANEL is extinguished and proceed to step (21).

(19) Should the 'LOW PRESSURE' lamp be lit, check for leaks (Refer to 21-52-00, pb601.) and, if found, take appropriate action to repair. Then proceed to step (21).

(20) Should no leaks be found then the following action should be taken:-

(a) Select the ON/FAN ONLY/OFF switches on both the FLIGHT COMPARTMENT CONTROL PANEL and the FLIGHT ATTENDANTS CONTROL PANEL to OFF.

(b) Connect shorting links across pins A and B of the low pressure switches in both forward and aft compressors and across the low pressure switch idented HEA11.

(c) Select the ON/FAN ONLY/OFF switch on the FLIGHT COMPARTMENT CONTROL PANEL to ON.

(d) Ensure that the 'COMPRESSOR' lamp is ON.

(21) Ensure that the flight deck is being supplied with cold air at high power.

(22) Ensure that the 'FORWARD COMPRESSOR' lamp on the FLIGHT ATTENDANTS CONTROL PANEL is lit.

(23) On the FLIGHT ATTENDANTS CONTROL PANEL, select the HI/LO switch for the forward cabin to LO and the FAN ON/OFF switch to ON.

(24) Ensure that the forward blowers are delivering cold air and are operating at low power.

(25) Select the HI/LO switch representing the forward cabin to HI.

(26) Ensure that the forward blower is delivering cold air and operating at high power.

(27) On the FLIGHT ATTENDANT CONTROL PANEL, select the ON/FAN ONLY/OFF switch to FAN ONLY, and the respective HI/LO switch to LO.

(28) Ensure that the aft blower is operating at low power.

(29) Select the HI/LO switch for the aft cabin to HI.



(30) Ensure that the aft blower is now operating at high power.

(31) Select the ON/FAN ONLY/OFF switch on the FLIGHT ATTENDANTS CONTROL PANEL to ON.

(32) Ensure the aft compressor lamp illuminates.

(33) Select the HI/LO switch representing the aft cabin to LO.

(34) Ensure that the aft blower is operating at low power and delivering cold air.

(35) Select the HI/LO switch representing the aft cabin to HI.

(36) Ensure that the aft blower is operating at high power and delivering cold air.

(37) Set the ON/FAN ONLY/OFF switch on the FLIGHT COMPARTMENT CONTROL to OFF.

(38) Ensure the forward compressor, the flight deck blower cease to operate and the appropriate lamps on the control panel all extinguish.

(39) Select the ON/FAN ONLY/OFF switch on the FLIGHT ATTENDANTS CONTROL PANEL to OFF.

(40) Ensure the 'AFT COMPRESSOR' lamp extinguishes.

(41) Ensure that the props are clear and arm the START MASTER switch.

(42) Select the START MASTER switch to ON.

(43) Select all HI/LO switches to LO.

(44) Select the ON/FAN ONLY/OFF switches on both control panels to ON.

(45) Ensure that the compressors do not operate.

(46) Select the ON/FAN ONLY/OFF switches to OFF.

(47) Select the START MASTER switch to NORMAL.

B. Test with engines running

(1) Select the ELECTRICAL MASTER switch to INTERNAL.

(2) Select both LEFT and RIGHT generators on line.

(3) Repeat para 1.A.(6) thru 1.A.(40).

(4) Trip the right generator.

(5) Ensure that the flight deck and forward cooling systems shut down.



(6) Ensure that all lamps indicating that the forward compressor is operative extinguish.

(7) Reset the right generator.

(8) Ensure that the flight deck and forward systems restart and that the lamps indicating the forward compressor is operative are illuminated.

(9) Trip the left generator.

(10) Ensure that the aft cooling system shuts down.

(11) Ensure that the lamp indicating that the aft compressor is operative extinguishes.

(12) Reset the left generator.

(13) Ensure that the aft system restarts and the aft compressor lamp is illuminated.

CAUTION: PERFORM THE FOLLOWING STEPS IF AND ONLY IF SHORTING LINKS WERE INSTALLED ACROSS THE LOW PRESSURE SWITCHES.

(14) Select the ON/FAN ONLY/OFF switch on the FLIGHT COMPARTMENT CONTROL PANEL and on the FLIGHT ATTENDANTS CONTROL PANEL to OFF.

(15) Disconnect the shorting links from the low pressure switches located in the compressors.

(16) Disconnect the shorting pins from low pressure switch HEA11.



AMM21-52-00 28.0.0.0FREON COOLING - INSPECTION/CHECK

1. Inspection/Check

WARNING: REFRIGERANT IS EXTREMELY COLD AND MAY CAUSE BURNS. HAND, EYE AND MOUTH PROTECTION SHOULD BE WORN AT ALL TIMES.

CAUTION: USE REFRIGERANT (R-L2) ONLY.

NOTE: This procedure should be carried out; after a new system plumbing is installed; after any plumbing system component is replaced; after any line or hose rupture.

A. Leak Inspection Check

(1) Remove the compressor-condenser access door located in the roof fairing.

(2) Disconnect the condenser hot air exhaust ducts.

(3) Remove the entire roof fairing.


(5) Remove the service port caps on the compressor.

(6) Connect the refrigerant charging manifold.

WARNING: THE HIGH PRESSURE HOSE (RED) MUST BE CONNECTED TO THE PORT MARKED 'D' AND THE LOW PRESSURE HOSE (BLUE) MUST BE CONNECTED TO THE PORT MARKED 'S'. AN INCORRECT CORRECTION CAN RESULT IN MANIFOLD DAMAGE AND/OR INCORRECT PRESSURE READINGS.

(7) Ensure that all manifold valves are off.

(8) Remove all shrouds and/or panels preventing access to the flight deck, forward and aft evaporators, listed in Table 601.

Table 601 (Sheet 1)

EVAPORATOR PANELS

FLIGHT COMPARTMENT 210CZFORWARD MODULE 261AZ

261CZ261JZ261KZ

AFT MODULE Door and end cap of the inboard locker at F.S. 475



(9) Remove any shrouds, panels or flooring or any other covering which prevents access to the refrigerant fittings or connections.

(10) Ensure that all plumbing connections are tight.

(11) Ensure the charging manifold is properly connected and the manifold charging hose is connected to the shut-off valve on the refrigerant can.

NOTE: The recommended can size is 0.88 lbs (14 oz.).

(12) Slowly open the can shut off valve until it is fully open.

(13) Slightly open the charging hose at the manifold inlet to exhaust air from the line.

(14) Tighten the charge hose fitting.

(15) Open both manifold valves to allow the contents of the can to enter the system.

NOTE: Both the high and low pressure gauges will indicate pressure in the system.


(17) Close the can shut-off valve.

(18) Remove the manifold charging hose from the can.

(19) Connect the manifold charging hose to a regulated dry nitrogen source.

(20) Remove the blue suction hose from the compressor service port.

(21) Open the high pressure (red) manifold valve.

(22) Regulate the nitrogen in the system until 250 - 255 pounds per square inch is indicated on the gauge.

CAUTION: DO NOT PUT EXCESSIVE PRESSURE IN THE SYSTEM OR DAMAGE MAY RESULT. REGULATE NITROGEN INTO THE SYSTEM SLOWLY.

(23) Apply soapy leak check solution to each connection to inspect for large leaks.

CAUTION: DO NOT USE ANY LEAK CHECK DYE IN THE SYSTEM OR DAMAGE MAY RESULT.

(24) Wipe off the soapy leak check solution if a large leak is not detected.

(25) Use the halogen leak detector to check all connections for small leaks.

NOTE: The halogen leak detector is very sensitive to leaks. Residual vapours may set off the detector prematurely. Therefore, be sure the work area is clear of all vapours. Use a high pressure air hose to blow the work area clear of all residual vapours.



(26) Tighten joints as required to stop all leaks.

CAUTION: DO NOT OVER TIGHTEN THE PLUMBING CONNECTIONS. STRIPPED THREADS OR CRACKED FLARES MAY RESULT.

(27) When the system is free of leaks, turn off the nitrogen supply.

(28) Disconnect the charging hose.

(29) SLOWLY vent the refrigerant and nitrogen gas from the system until zero pressure is reached.

(30) Close the manifold valve.

(31) Reconnect the blue hose to the compressor suction service valve.

(32) Connect a full can of refrigerant to the charging hose.

(33) Open the can hand valve.

(34) Loosen the manifold hose fitting slightly and allow any air to clear out of the line.

(35) Open both manifold valves to allow the contents of the can to enter the system.

(36) After system pressure is established, close both manifold valves.

(37) Close the can hand valve and disconnect the charging hose.

(38) Slowly open both manifold valves and vent the system until internal pressure is 2 - 5 psig.

CAUTION: VENT THE SYSTEM VERY SLOWLY TO ENSURE THAT COMPRESSOR OIL IS NOT VENTED WITH THE REFRIGERANT. DO NOT LET AIR ENTER THE SYSTEM.




AMM21-52-05 29.0.0.0COMPRESSOR/CONDENSER MODULE - SERVICING

1. Servicing

A. Drive belt alignment procedure

WARNING: ALL BOLTS AND NUTS MUST BE TIGHTENED SLIGHTLY BEFORE ALIGNMENT; OTHERWISE MAJOR BELT AND/OR COMPRESSOR DAMAGE MAY RESULT.

(1) If required, loosen the motor pulley set screws.

(2) Rotate the compressor pulley clockwise.

(3) Simultaneously, slide the motor pulley forward or aft until the belt rides directly over the compressor pulley.

(4) Slightly tighten the motor pulley set screws.

(5) Rotate the compressor pulley for approximately 10 revolutions.

(6) Ensure that the belt is correctly tracking in the pulley.

(7) Tighten the set screws.

B. Drive Belt Tensioning Procedure

Special Tool(s)

Spring loaded force gauge.

WARNING: DO NOT OVER TENSION THE BELT, OTHERWISE BELT OR MOTOR DAMAGE MAY OCCUR.

(1) Ensure that all bolts are tightened slightly.

(2) Ensure that the belt is properly aligned.

(3) Rotate the rod-end adjustment nut counterclockwise.

(4) Apply belt tension until a deflection of 0.10 in. (2.5 mm) is noted when a load of 3.25 to 3.5 lb is applied at a point midway between the two pulleys.

(5) When proper belt tension is obtained, tighten the two compressor bolts and the two rod-end nuts. (Torque to 160 - 190 in/lb).



AMM21-52-05 30.0.0.0COMPRESSOR/CONDENSER MODULE - REMOVAL/INSTALLATION


A. Remove a compressor/condenser module.

(1) Evacuate the appropriate system.

(2) Disconnect the high end and low pressure hoses and cap off.

(3) Remove the pressure switch connections.

(4) Remove and retain the four bolts and wedges from the base plate and mounting track.

(5) Slide the mounting tracks from the compressor/condenser assembly.

B. Install a compressor/condenser module

(1) Slide the mounting tracks onto the compressor/condenser base assembly.

(2) Place the compressor/condenser module on the mounting tray.

(3) Replace the four bolts and wedges.

(4) Tighten the bolts.

(5) Replace the pressure switch connections.

(6) Replace the low and high pressure hoses.

(7) Charge the system.

C. Remove a compressor

(1) Render the aircraft electrically safe.

(2) Remove access doors, exhaust ducts and roof fairing (panels 240EL, 240BR, 240ER, 240DL and 240HL) to gain access to the compressors.

(3) Connect the refrigerant manifold gauge and hose assembly to the compressor suction and discharge valves.

(4) Slowly vent the system to zero pressure and disconnect the manifold assembly.

CAUTION: VENTING THE SYSTEM QUICKLY WILL RESULT IN AN EXCESSIVE LOSS OF REFRIGERANT OIL.

(5) Remove the cables from the pressure switch connections.

(6) Loosen the compressor support and adjustable bolts and swing the compressor down.



(7) Remove the belt guard and drive belt, taking care not to damage the belt - refer to para 1.H.

(8) Remove the system suction and discharge hose and cap-off immediately.

(9) Remove the compressor adjustment and support bolts.

(10) Remove the compressor from the mounting bracket.

D. Install a compressor

NOTE: If the compressor being replaced has contaminated the system, a complete cleaning and flushing of the system is required. The receiver dryer unit must also be replaced. Flush the system with refrigerant and then nitrogen. Also remove and clean the expansion valves.

(1) Lift the compressor onto the support bracket and install the support bolts, washers and nuts.

(2) Place the rod end bearing onto the adjustment hole in the motor support bracket and install the washer and nut.

(3) Tighten the compressor support nuts and position the compressor in the full down position.

(4) Install the drive belt, taking care not to damage the belt or the motor pulley flange.

(5) Align and tension the belt.

(6) Replace the belt guard.

WARNING: IN THE FOLLOWING STEP, REMOVE THE CAPS AND VENT SLOWLY.

(7) Remove the compressor suction and discharge fitting caps and connect the system hoses.

(8) Apply a small amount of refrigerant oil on the compressor fitting(s) flare and a small amount of thread sealant on the fitting threads.

NOTE: Do not apply sealant to the first three threads.

(9) Tighten the fitting nuts to 160 - 200 in.lb.

NOTE: Do not exceed 200 in.lbs.

(10) Connect the contactor control wire to the low pressure switch wire terminal located on the discharge fitting.

(11) Connect the manifold gauge and hose assembly to the suction and discharge service ports.



(12) Apply 3 oz. of Suniso 5GS viscosity oil to the compressor. Apply the oil to the port located between the service ports at the top of the compressor.

NOTE: If the failed compressor did not contaminate the system, no additional oil is required. The new compressor contains the required charge. The receiver-dryer unit must be replaced.

(13) Inspect the system for leaks.

(14) Charge the system -

(15) Function test the system.

E. Remove a drive motor


(2) Remove all access panels, exhaust ducts and roof fairing (panels 240 EL, 240 BR, 240 ER, 240 DL, and 240 HL) to gain access to the compressors.

(3) Remove the belt cover, drive belt, fan shroud and condensor fan.

(4) Disconnect the power leads, identify and tag.

(5) Remove the eight mounting bolts from the support bracket, ensuring that the motor does not fall on the power contactor.

(6) Remove all cables tie strapped to the motor.

(7) Raise the motor slightly and pull it out to remove it from the mounting bracket.

(8) When the motor is free from the mounting bracket, remove the drive pulley.

F. Install a drive motor

(1) Install the drive pulley on the short motor shaft.

(2) Tighten the set screws.

(3) Slide the motor onto the mounting bracket.

(4) Ensure the long end is positioned through the hole in the condenser coil.

(5) Replace the motor support bolts and lock washers (torque to 10 - 15 lb).

(6) Install two flat washers on the long motor sbaft end.

(7) Slide on the fan assembly (one set screw should be positioned over the flat surface of the motor shaft).



(8) Install the flat washer and lock nut.

(9) Tighten the set screw on the flat surface of the shaft.

(10) Torque the lock nut.

(11) Tighten the other set screw.

(12) Replace fan shroud, ensuring the fan blade does~not rub on the shroud and seal the shroud with RTV sealant.

(13) Connect the power leads.

(14) Replace the drive belt - refer to para 1. H.

(15) Align the drive belt.

(16) Tension the belt.

(17) Install the belt guard assembly and secure it.

(18) Re�tie all cables.

(19) Perform a function test to ensure the system and motor are operational.

G. Remove a drive belt


(2) Remove all access panels, exhaust ducts and roof fairing (panels 240EL, 240BR, 240ER, 240DL and 240HL) to gain access to the compressors.

(3) Remove all fasteners securing the belt guard assembly.

(4) Slightly loosen the two bolts supporting the compressor.

(5) Rotate the tension nut clockwise to loosen the compressor side of the rod end bearing.

(6) Swing the compressor down to loosen the belt.

(7) Loosen the socket head screws in the motor pulley.

(8) Slide the pulley of the motor shaft while sliding the drive belt off the compressor pulley.

WARNING: DO NOT BEND OR EXCESSIVELY TWIST THE DRIVE BELT DURING REMOVAL OR DAMAGE MAY RESULT.



H. Install a drive belt

(1) Verify the belt size and part number before installing as using the wrong part may damage the unit.

(2) Ensure that the rod end adjustment nut is positioned at the end of the threads.

(3) Swing the compressor to the lowest position.

(4) Place the belt on the motor pulley.

(5) Slide the pulley on to the end of the motor shaft.

(6) While sliding the belt over the compressor pulley, slightly rotate both pulleys to ensure a proper fit.

(7) Lightly tap the motor pulley onto the shaft until the belt completely ~overs the compressor pulley.

(8) Ensure that the belt teeth are in the grooves of each pulley.

(9) After the belt is installed, rotate the compressor pulley clockwise to align the belt and pulley.

(10) Ensure that the belt rides directly over the compressor pulley.

(11) Should the belt be too far forward or aft it must be realigned - Refer to 21-52-05, pb301.

(12) After the belt is aligned properly, slightly tighten the two compressor support nuts.

(13) Turn the rod-end bearing adjust nut until it is flush against the support.

I. Remove a drive motor brush

(1) Remove the compressor/condenser module from the aircraft - Refer to para 1.A.

(2) Using a stiff wire hook or scribe, lift the brush springs from the holders and remove all four brushes.

(3) Remove all four brush shunt wire terminal screws and lock washers.

J. Install a drive motor brush

(1) Make sure the brushes are servicable; discard the worn brush sets.

(2) Ensure the motor commutator is clear of any contamination or carbon dust.

(3) Install each new brush set by lifting the brush springs and sliding the brush into the holder with the brush leading edge in the direction of rotation.



(4) SLOWLY, release the brush spring onto the brush.

(5) Ensure the brush is seated flatly on the commutator and that there is no binding in the holder.

(6) Align the brush spring in the centre of the brush groove.

(7) Install the terminal screw and lock washer on the brush shunt lead and other leads and tighten the screw. Repeat for all sets.

(8) Seat the brushes properly using the following procedure.

(a) Cut a 4" x 15" strip of 400 - 500 emery paper.

(b) Place the strip, with the rough side out, on the motor commutator.

(c) Secure one end of the paper to the commutator with masking tape. Position the strip so the taped end will lead in the direction of rotation.

(d) The opposite end should remain loose and overlap the taped end.

(e) Raise each brush while rotating the shaft until the taped end has passed under each brush.

(f) When the emery paper is positioned against the commutator and covers the entire brush surface area, carefully rotate the armature, by hand, in the normal direction of rotation until a full seat is obtained in each new brush.

(g) Remove the emergy paper and blow out all carbon dust from the commutator and brush area.

(9) Carefully position the brush shunt leads so that any shorting problems are prevented.

(10) Replace the brush cover and all power leads.

(11) Inspect the motor to ensure that the cuff assembly and the condenser support bracket are installed.

(12) Ensure that the motor drive belt is installed, aligned and tensioned and that the belt cover is installed.

(13) Install the compressor/condenser module - Refer to para 1.B.

(14) Verify proper operation by running the system for at least 15 minutes.



AMM21-52-05 31.0.0.0COMPRESSOR/CONDENSER MODULE - INSPECTION/CHECK

1. Inspection/Check

A. Inspect the compressor

CAUTION: PROTECTIVE GLASSES AND GLOVES MUST BE WORN DURING THIS CHECK.


(2) Remove access doors, exhaust ducts and roof fairing (panels 240EL, 240BR, 240ER, 240DL and 240HL) to gain access to the compressors.

(3) Remove the belt cover and check the belt for alignment and tension.

(4) Inspect the compressor output shaft for excessive oil leaks.

NOTE: If excessive oil is noted, the compressor should be checked for leaks using fluid or leak detector. If a leak is detected the compressor should be replaced.

(5) Ensure that all fasteners are securely tightened.

(6) Re-torque where necessary.

(7) Inspect the drive belt for cracks, wear or excessive oil.

(8) Using a clean rag, clean all oil and other contamination from the belt cogs.

(9) If the visual inspection is satisfactory, replace the belt cover and tighten the fasteners.

B. Inspect the motor brushes

WARNING: EYE AND MOUTH PROTECTION MUST BE USED DURING THIS PROCEDURE FAILURE, TO DO SO MAY RESULT IN EXCESSIVE LUNG AND EYE IRRITATION.

CAUTION: DO NOT DIRECT THE AIR JET ONTO THE MOTOR BEARINGS.


(2) Remove access doors, exhaust and roof fairing (panels 240EL, 240BR, 240ER, 240DL and 240HL) to gain access to the compressors.

(3) Remove the compressor/condenser module from the aircraft.

(4) Disconnect the power leads from the motor terminals.

(5) Identify and tag the positive lead.

(6) Remove the condenser support bracket to provide access to the brush cover fasteners.



Brush Wear Rate CheckFigure 601



(7) Loosen and unsnap the brush cover assembly and remove the assembly from the motor.

(8) Using a wire hook or scribe, lift the brush spring and remove the brush.

(9) Inspect the brush for cracks, chipped edges, frayed leads, loose rivets or shunt connections.

(10) Replace the brush if defective.

(11) Repeat this procedure for all brushes. All brushes should show uniform wear.

(12) Inspect the brush holders and springs for looseness, - arcing, heat distortion or cracks.

(13) Refer to Figure 601. Measure dimension 'A' of each brush and record the values.

(14) Using the brush with the shortest measured length calculate the 'wear rate' by subtracting the measured length from 1.000 inch and dividing by the number of hours operated.

(15) Calculate the remaining brush life by subtracting 0.450 inch from the measured brush length and dividing by the calculated 'wear rate'.

WARNING: BRUSHES MUST BE CHECKED PRIOR TO THE REMAINING CALCULATED BRUSH LIFE HOUR, OTHERWISE DAMAGE TO THE MOTOR MAY RESULT.

(16) While the brushes are removed for inspection, the commutator must be inspected for excessive or uneven wear.

(17) The commutator should have a burnished appearance with light filming. If the commutator is black, burned or excessively worn or if the remaining depth of mica undercut on the commutator is less than 5 mm, the motor should be replaced.

(18) Replace existing brushes in brush holder.

(19) Ensure the leading edge of each brush is pointing in the direction of rotation of the commutator.

C. Motor Bearing Inspection


(2) Remove the brushes from the brush guides - refer to para 1.B.

(3) Remove the belt from the motor pulley.

(4) Rotate the motor shaft with your fingers to check for smoothness.

(5) If the bearings feel rough or sound dry, replace the motor.

(6) If bearings are operating correctly, install the belt and brushes.



(7) Check belt alignment and tension.

(8) Replace brush cover.

(9) Tighten the clamp nuts.

(10) Connect the power leads to the motor terminals and tighten the nuts.

D. Motor Insulation Resistance Check


(2) Disconnect all power leads.

(3) Connect the OHM meter positive to the positive motor terminal.

(4) Connect the negative lead to the motor case ground.

(5) Measure and record the resistance.

(6) The resistance valve must be equal to or greater than 10000 ohms. If the value is less than 10000 ohms, replace the motor.

E. Inspect for Internal Contamination of the drive motor

(1) Ensure that is no foreign material lodged in the motor air intake or in the motor field winding areas.

(2) Inspect the motor for excessive moisture or corrosion of the parts.

(3) Using an air hose, clear the motor air passages of any dust, dirt or other contamination.

F. Compressor Oil Level Check

NOTE: This procedure must be followed when a compressor has failed and been replaced.

(1) Drain and measure the amount of oil from the failed compressor.

(2) Add the same amount of new oil to the new compressor.

CAUTION: DO NOT OVERFILL THE COMPRESSOR WITH MORE OIL THAN WAS DRAINED; OTHERWISE SYSTEM PERFORMANCE WILL BE AFFECTED.

NOTE: Only 500 viscosity oil should be used in these compressors. Use Suniso 5GS oil or and equivalent oil.



AMM21-52-10 32.0.0.0EVAPORATOR AND BLOWER MODULE(S) - REMOVAL/INSTALLATION


A. Remove a flight deck blower motor

(1) Remove panel 210CZ.


(3) Evacuate the forward system.

(4) Disconnect the drain, suction and discharge hoses and cap off.

(5) While supporting the evaporator, remove bolts A, B, C and D.

(6) Remove the motor wire clamp.

(7) Disconnect the wire splice from the resistor wire.

(8) Remove all other electrical connections, noting wire colours, connections and terminations.

(9) Remove the four motor mounting screws.

(10) Using a small knife, slide the tool between the motor and the plastic scroll to cut the RTV sealant bonding.

(11) Lift the blower motor out of the scroll assembly.

(12) Remove the blower wheel.

(13) Discard the blower motor.

B. Install a flight deck blower motor

(1) Replace the motor wheel on the new motor shaft, ensuring the back of the wheel is 0.25 inches from the motor mounting surface.

(2) Ensure the set screw on the wheel of the hub is located on the flat section of the motor shaft.

(3) Apply thread lock sealant to the set screw threads.

(4) Tighten the set screw.

(5) Rotate the blower wheel on the motor shaft to check for any rocking of the wheel.

(6) Apply a light force on the outside diameter of the wheel to eliminate any rocking.



Blower Motor RemovalFigure 401



(7) Apply a small bead of RTV sealant on the scroll.

(8) Install the blower wheel and motor with the motor wires positioned near the resistor wires and mounting screw.

(9) Install and tighten the mounting screws.

(10) Using the access through the blower outlet, rotate the blower wheel to ensure that no rubbing exists.

(11) Connect the motor and resistor wiring as follows.

Clockwise Rotation

(a) Butt connect the red motor wire to the orange resistor wire and connect to the appropriate cable.

(b) Butt connect the red resistor the appropriate cable.

(c) Connect the black cable to the appropriate earth point.

Anti-clockwise rotation

(d) Butt connect the black motor wire to the orange resistor wire and connect to the appropriate cable.

(e) Cover the red motor wire with black heatshrink and connect to the appropriate earth point.

(f) Butt connect the red resistor wire to the appropriate cable.

(g) Route all cables through the wire clamp and secure with mounting screw and washer.

(h) Connect power leads to the blower assembly and test for operation.

(12) Install the evaporator and replace bolts A, B, C and D.

(13) Remove drain, suction and discharge hose caps and connect to the system.

(14) Replace panel 210CZ.

C. Remove a forward blower motor

(1) Remove panels 261CZ and 261AZ. Refer to Figure 401.






(5) Remove all other electrical connections, noting wire colours, connections and terminations.






D. Install a forward blower unit.











(11) Connect the motor and resistor wiring as follows:

Clockwise Rotation





(c) Connect the black cable to the appropriate earth point.

Anti-clockwise rotation

(d) Butt connect the black motor wire to the orange resistor wire and connect to the appropriate cable.

(e) Cover the red motor wire with black heatshrink and connect to the appropriate earth point.

(f) Butt connect the red resistor wire to the appropriate cable.

(g) Route all cables through the wire clamp and secure with mounting screw and washer.

(h) Connect power leads to the blower assembly and test for operation.

(12) Replace panels 261AZ and 261CZ.

E. Remove an aft blower motor.

(1) Evacuate the aft system.


(3) Disconnect suction, pressure and drain tubes and cap off immediately.

(4) Remove the two air ducts connecting the lower assembly and the evaporator/blower module.

(5) Note and record wire colours connections and terminations.

(6) Remove all electrical connections.

NOTE: It may be necessary to remove the locker end cap.

(7) Remove the five bolts connecting the locker floor to its frame.

(8) Lift the locker floor and slide out.










F. Install an aft blower motor











(11) Connect the motor and resistor wiring as follows;

NOTE: With the aft module it will be necessary to wait until unit is installed in the locker.

Clockwise Rotation



(c) Connect the black cable to the appropriate

(d) earth point.

Anti-clockwise Rotation

(e) Butt connect the black motor wire to the orange resistor wire and connect to the appropriate cable.



(f) Cover the red motor wire with black heatshrink and connect to the appropriate earth point.

(g) Butt connect the red resistor wire to the appropriate cable.

(h) Route all cables through the wire clamp and

(i) secure with mounting screw and washer.

(j) Connect power leads to the blower assembly and test for operation.

(12) Slide locker floor into place and replace the five bolts.

(13) Remove suction, pressure tube and drain caps and connect the system tubes.

(14) Replace the two air ducts.


G. Remove an evaporator expansion valve

WARNING: EYE AND HAND PROTECTION SHOULD BE WORN DURING THIS PROCEDURE. CAP ALL OPEN SYSTEM PORTS.

(1) Vent the system to zero internal pressure.

(2) Remove all evaporator shrouds and enclosures.

(3) Remove the valve inlet tubing.

(4) Remove the valve from the coil tubing header.

(5) Inspect the valve inlet filter for contamination and clean if required.

(6) If an contamination is noted, replace the valve.

H. Install an evaporator expansion valve

(1) Set the new valve alignment screw at the same position as the failed valve.

(2) Apply a small amount of thread sealant to the valve inlet and output port threads.

(3) Apply a very small amount of refrigerant oil to the valve port flare surfaces.

(4) Install the valve in the coil and header and position as required.

(5) Tighten the connection using a torque wrench.



CAUTION: DO NOT OVER TORQUE NUT 'B'.

(6) Connect the valve inlet port tubing and tighten.

(7) Check the system for leaks and vacuum.


(9) Test the system.



AMM21-52-10 33.0.0.0EVAPORATOR AND BLOWER MODULE(S) - INSPECTION CHECK

1. Inspection/Check

A. Evaporator Coil Inspection

(1) Inspect for excessive lint and/or contamination in the coil fins.

(2) Clean as required using a vacuum or low pressure air source.

B. Condensate Drain and Tubing Inspection

(1) Ensure that the evaporator condensate drain and associated tubing are not blocked or kinked and have a continuous fall to the drain outlet.

(2) Clean or re-route if required.

C. Cool Air Ducting Inspection

(1) Inspect the cool air ducting from the evaporator blower for excessive air loss from loose connections or cracked hoses.

(2) Tighten connections or replace the hoses as required.



AMM21-61-00 34.0.0.0PASSENGER COMPARTMENT TEMPERATURE INDICATION - DESCRIPTION & OPERATION

1. Description

Crew indication of temperature in the passenger compartment is provided by a gauge mounted on AIR CONDITIONING panel 9P. The gauge is calibrated from 0°C to 100°C and operates in response to a temperature sensitive bulb located in the extraction duct above the galley units.

2. Power Supplies

Power supplies are derived from the 28 V d.c. essential services busbar- right via 5 amp circuit breaker No. 196 on distribution panel 2D.

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