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HVAC InstallationProcedures Contents

THE ORGANIZED INSTALLATION 1

INTRODUCTIONThis section provides the basic information needed to plan and prepare for the installation ofresidential and light commercial air conditioning and heating systems. Planning the installationand an overview of the tasks and sequence for a typical installation are covered first, followed bya brief description of the tools used to perform common installation tasks. Also given in thissection are guidelines for acquiring and maintaining good customer relations before, during, andafter the installation.

SECTION 1

THE ORGANIZED INSTALLATIONNt

THE ORGANIZED INSTALLATION 1

PLANNING THEINSTALLATIONReliable system installations do not happen byaccident; they require careful planning(Figure 1-1). Local ordinances governing equip-ment placement, electrical hookup, materials,and the protection of the environment must beobeyed. This is necessary to avoid any incon-venience, increased cost, and bad reputationresulting from a failed inspection. Constructionpermits must be secured in some localities. Thespecific site for indoor and outdoor equipment,as well as any ductwork and piping, must beidentified and prepared to receive the equip-ment.

The proper type of equipment for the job mustbe selected and ordered. Ducting, piping, andelectrical materials must be selected and pur-chased by a qualified engineer or salespersonbased on a survey of the job. For new construc-tion, this survey may be done by consulting thebuilder and looking at the blueprints and speci-fications for the job.

For a replacement job, the survey is com-pleted by visiting the job site and consulting withthe customer to determine their needs. Heat-ing and cooling load estimates for the buildingare made and the existing air distribution sys-tem, utilities, and electrical service areevaluated to determine their adequacy to sup-port the new equipment.

TYPICAL INSTALLATIONTASKS AND SEQUENCEThe installation of any system or componentshould always be performed as recommendedby the manufacturers specific installation in-structions. This is because the actual tasks andtheir sequence can vary widely based on thesize and type of system being installed. A typi-cal approach is to start by preparing thelocation and setting the equipment in place(Figure 1-2). Electrical wiring is run to theequipment location or to a disconnect whichfeeds the equipment. Local codes may requirethat this be done by a licensed electrician.Ductwork and combustion vents are connectedto the equipment as needed. This is followedby the installation and connection of the refrig-erant, gas, and condensate piping to theequipment, as required. The final electricalhookup is made to the thermostat and to theunits control circuits.

t Figure 1-1.Planning

EQUIPMENT MATERIALS PERMITS AND CODES SELECT EQUIPMENT LOCATION(S) PREPARE EQUIPMENT SITE(S) SCHEDULE JOB/COORDINATE WITH OTHER TRADES INSTALL/START UP/CHECK OUT

t Figure 1-2.Installation Sequence

EQUIPMENT PLACEMENT RUN WIRING (ROUGH IN) RUN DUCTING WITH FINAL CONNECTION RUN PIPING WITH FINAL CONNECTION ELECTRICAL HOOKUP

THE ORGANIZED INSTALLATION 1

t Figure 1-5.Typical Hand Tool Set

t Figure 1-3.Commissioning

t Figure 1-4.Confirm Correct Installation Using Installation andStart-Up Checklists

Following completion of the initial installationtasks, the system must be readied for service(Figure 1-3). This often requires that the refrig-erant and gas lines be leak-tested and, ifnecessary, repaired. If installing a field-pipedcooling system, the system must be evacuatedand the refrigerant charge checked. During thisstep, it is essential to follow all installation in-structions and guidelines provided by themanufacturer. Next, the equipment start-up pro-cedure is performed to check the operation ofthe equipment, make adjustments, and checkout the operation of all safety controls.

The final step is a thorough cleanup of theequipment and the work area. You should alsogive the customer the owners manual(s) alongwith simple, courteous instructions on how tooperate and maintain the system.

INSTALLATION AND START-UP CHECKLISTSMost manufacturers provide installation andstart-up checklists (Figure 1-4) in the literaturesupplied with their equipment. At appropriatepoints throughout the installation, these check-lists should be used to confirm the completionof various installation tasks. During systemcheckout, the lists are used to record the unitsperformance characteristics.

INSTALLATION TOOLS ANDEQUIPMENTA quality installation depends on using the righttools and equipment for the job. General-pur-pose tools and equipment are described here.Specialized tools and equipment are described,where relevant, later in this book.

Hand Tool SetYou should have a tool box equipped with avariety of quality hand tools (Figure 1-5). Spe-cialized tools needed to service refrigerationsystems such as service valve adapters, etc.should also be included in this tool set.

Measuring and Layout ToolsMeasuring and layout tools used to determinelength, height, diameter, levelness, or plumbmust be easy to use, accurate, and durable.Common measuring tools include: Measuring tapes and folding rules Squares Levels Plumb bobs and chalk lines

1. LEAK TEST AND REPAIR IF NEEDED2. EVACUATE AND DEHYDRATE3. CHARGE SYSTEM (REFRIGERANT AND ANY EXTRA OIL)4. INSULATE REFRIGERANT LINES5. FINAL INSPECTION6. START UP AND CHECK OUT7. CLEAN UP8. CUSTOMER INFORMATION/INSTRUCTION

LEAKDETECTORSOLUTION

BEEP

BEEP

CHECK

LIST

THE ORGANIZED INSTALLATION 1

t Figure 1-6.Folding Rule and Measuring Tape

Folding rules require little mainte-nance, except for periodic lubricationof the joints.

Avoid dropping a folding rule as thefall may loosen the joints enough tocause inaccuracies.

To work properly, steel tapes mustbe kept clean, dry, and free of kinks.

Keep water and mud out of the steeltape case as they can cause rustand other damage to the rewindmechanism.

Measuring Tapes and Folding Rules Mea-suring tapes and folding rules (Figure 1-6) areused for making most measurements. Theyare normally marked with both English andmetric scales.

Folding rules come in 6- to 10-foot lengths,with hinges for folding. Some are equippedwith a graduated sliding brass extension thatis useful for making depth and inside measure-ments. Because of its stiffness, a folding ruleis useful for making overhead and verticalmeasurements.

Self-rewinding measuring tapes are madeof steel or fiberglass and usually come in 10-to 30-foot lengths. A hook on the end of therule grabs onto the work piece, making it easierto use when making long measurements. Alock holds the tape in the open position and arewind mechanism retracts the tape when notin use. Longer tapes are available for mea-suring longer lengths.

Squares Squares are used for measuring,marking a line for cutting, checkingsquareness, and checking the flatness of ma-terials. Two kinds of squares are commonlyused: a combination square and a framing orcarpenters square.

The combination square (Figure 1-7) con-sists of a blade and a sliding adjustable head.The blade and head incorporate a 90 squareand a 45 miter square that allow the tool tobe used to check and/or mark out either 90or 45 angles. Most combination squares havea built-in spirit level and a hardened scriberthat can be used for marking metal.

Carpenters squares (Figure 1-8) are usedmainly as a straightedge and to mark out right-angle lines. They are also used to check theinside and outside squareness and flatnessof materials. Both the body and tongue arestamped with graduations that are divided intoinches, allowing the tool to be used as a ruler.Framing squares usually have tables and for-mulas marked on them to make calculationsfor area and volume.

12

345

6

QUICK NOTE

t Figure 1-7.Combination Square

BLADE

HEAD

t Figure 1-8.Carpenter's Square

TONGUE

BODY

THE ORGANIZED INSTALLATION 1

Levels Levels are used to determine the hori-zontal (level) or vertical (plumb) alignment ofstructural members, piping, or mounted com-ponents. Levels are made in simple andelectronic models and come in various lengths.A general-purpose spirit level (Figure 1-9) isnormally adequate for use in HVAC installationwork.

Common spirit levels have three vials. Thetwo end vials are used to measure verticalplumb while the center vial is used to measurehorizontal level. The item being checked is levelor plumb when the air bubble within the appro-priate vial is centered between the lines etchedon the vial.

When not in use, levels should be stored ina manner that ensures they will not be twisted,bent out of shape, or have their vials broken.

Plumb Bobs and Chalk Lines Plumb bobs(Figure 1-10) are balanced weights used to findplumb over long vertical distances. When sus-pended from a height by a string attached to itsexact top center, and allowed to hang freely,the force of gravity causes the plumb bob stringto settle in the plumb position.

A chalk line (Figure 1-11) is used to mark alayout line between two points on long flat sur-faces. It typically consists of a case filled withchalk and a length of line on a retractable reel.Each time the chalk line is pulled out of the box,it is automatically chalked. To use a chalk line,the line is pulled from the case, stretched tautbetween the two reference points to be con-nected, then snapped. This causes the chalkon the line to mark the surface underneath thestring. The chalk line must always be kept in adry place, or moisture may cause it to becomeclogged.

Portable Electric andCordless ToolsA variety of electric and/or cordless hand drills,saws, etc. are used regularly on installations.Electric tools normally operate on 110-120 voltsAC, and are plugged into an outlet near the worklocation.

Cordless drills (Figure 1-12) and othercordless tools are useful for working where elec-trical outlets are not available. Cordless toolshave a detachable and rechargeable batterypack that runs the motor. Generally, the higherthe voltage rating of the battery pack, the higherthe torque or capacity of the tool. Most qualitytools have chargers that can quickly rechargethe battery pack. However, an extra batterypack should be purchased so that the job isnever halted while waiting for a battery to re-charge.

t Figure 1-9.Spirit Level Used to Check Plumb and Level

LEVEL VIAL

PLUMB VIAL

t Figure 1-10.Finding True Vertical Plumb with a Plumb Bob

PLUMB BOB

STRING

t Figure 1-11.Mechanical Chalk Line

HOOK

LINE

CASE

HANDLE

t Figure 1-12.Cordless Driver-Drill and Charger

Power-Driller5000

Charg

er 50

00

THE ORGANIZED INSTALLATION 1

Electric and Cordless Drills The specificdrill used depends on the diameter, depth ofthe hole, and type of material to be drilled(Figure 1-13). Drills are rated according to themaximum horsepower (hp) developed by themotor. Generally, the higher the hp, the morepower or torque is available to the drill.

Drills are also rated by the largest drill bit(Figure 1-14) shank that the chuck will hold.Chuck size is a good indication of the largestsize hole the drill can easily bore through hardmetal. Drills can be fitted with 1/4-inch, 3/8-inch,or 1/2-inch chucks.

Drills with variable-speed and rotation-revers-ing features are desirable for installation work.Reversing the rotation of the drill makes it easierto release stuck and jammed bits and to re-move screws, etc. Variable speed allows holesto be drilled at different speeds. Generally, theharder the material being drilled, the slower thedrilling speed. Drilling iron or steel is best doneat speeds in the range of 300 to 500 rotationsper minute (rpm), while drilling in softer materi-als such as wood is better done at higherspeeds up to about 1,200 rpm. The use of veryslow speeds also makes it easier to start holes,run in screws, and perform other similar opera-tions.

A hammer drill (Figure 1-15), so named be-cause of its hammering action, is commonlyused to drill holes into masonry. It rotates andhammers at the same time and drills muchfaster than regular drills. Hammer drills have adepth gauge that can be set to control the depthof the hole being drilled.

Circular, Reciprocating, and Jig Saws In-stalling HVAC equipment requires that holes becut for pipes, ductwork, vents, etc. Wood andother materials must also be cut to build sup-port structures for equipment and/or to mountelectrical and other panels. These cutting jobsare normally done using circular, reciprocating,and/or jig saws.

QUICK NOTEBefore drilling, make sure work isfirmly supported and clamped. Make astarter hole with an appropriate punchto prevent the bit from wandering.

t Figure 1-13.Electric Drill Used to Drill Hole in Metal I-Beam

t Figure 1-14.Types of Drill Bits

HOLE SAWCOUNTERSINK

BIT EXTENSION

POWERWOOD

BIT

BRAD-PT.WOOD

BIT

WOODSCREW

PILOT BIT

MASONRYBIT

WOOD PLUG CUTTER

TWISTDRILLS

t Figure 1-15.Hammer Drill Used to Drill Holes in Masonry

THE ORGANIZED INSTALLATION 1

Circular saws (Figure 1-16) are used to makestraight cuts in various materials. The size of acircular saw is determined by the diameter ofthe largest blade that can be used with the saw,which determines how thick a material can becut. Saws using blades of 7-1/4 and 8-1/4inches are the most popular. Circular saws haveupper and lower guards that surround the blade.The upper guard is fixed; the lower guard isspring-loaded and retracts as the saw cuts intothe work piece. The saw baseplate rests on thematerial being cut and can be adjusted tochange the depth of the cut or to make bevelcuts ranging between 0 and 45.

There are a wide variety of blades available,each designed to make an optimum cut in adifferent type and/or density of material. Gen-erally, blades are standard steel orcarbide-tipped. Carbide-tipped blades staysharper longer, but they are more brittle andcan be damaged if improperly handled. Thenumber of teeth on a blade, the grind of eachtooth, and the space between the teeth (gulletdepth) determines the smoothness and speedof the cut. To select the right blade, use a bladerecommended by the blade manufacturer forthe type of material being cut. Make sure thatthe blade diameter, arbor hole size, and maxi-mum rotation speed fit your saw.

Reciprocating saws (Figure 1-17) are heavy-duty saws with a back-and-forth blade motion.They can be used for cutting through floors andpartitions including nails, wire mesh backedplaster, studs, and beams. Variable-speed mod-els with speeds ranging from 0 to 2,400 strokesper minute (spm) are best. Higher horsepowerand slower speeds are generally needed whencutting through metals or when cutting along acurved or angled line. The typical length of thehorizontal sawing stroke is 1-1/8 inch. A goodsaw will have the capability of mounting the sawblade so cuts can be made upward as well asto the left and right.

A jig or saber saw (Figure 1-18) is a lighter-duty saw than the reciprocating saw and is usedto make straight or curved cuts. With the properblade, it can cut wood, metal, plastic, and othermaterials. Variable-speed models with speedsranging from 0 to 3,200 spm are best. The typi-cal length of the vertical sawing stroke is oneinch. Other features of a good saw include ad-justable orbital action to clear away chips, abaseplate that can be tilted for bevel cuts, anda scrolling capability that makes it easier to cutalong pattern lines.

t Figure 1-16.Circular Saw

CARBIDE-TIPPED ABRASIVE

STEEL MASONRY

QUICK NOTE A circular saw with a large diameter blade is of little value if the saw motor lacks the horsepower

to drive it. If adequately powered, a saw with no-load blade speeds ranging between 4,000 and 5,800 rpm

makes a faster, smoother cut than one that runs at a lower speed. Too much cutting blade depth increases the chance of saw kickback and can cause the cut to be

rough. For standard steel blades, allow one whole tooth to project below the material to be cut.For carbide-tipped blades, allow 1/2 a tooth.

t Figure 1-17.Reciprocating Saw Cutting through a Floor

t Figure 1-18.Jig (Saber) Saw

THE ORGANIZED INSTALLATION 1

A wide variety of interchangeable blades aremade for use with reciprocating and jig/sabersaws. Each type of reciprocating or jig/sabersaw blade is designed to make an optimum cutin a different kind of material. Always use theblade recommended by the blade manufacturerfor the type of material being cut.

Portable Band Saw The portable band saw(Figure 1-19) is useful for cutting heavy met-als. Typical cutting capacities are up to 3-1/2inches for round materials and 3-1/2 x 4-1/2inches for rectangular materials. The band sawhas a continuous one-piece blade that runs inone direction around guides located at eitherend of the saw. Two-speed and variable-speedmodels are both common. Band saw bladesare made with standard pitch or variable pitchteeth. Blade materials and the number and pitchof the teeth are designed to make an optimumcut in different kinds of materials. Always usethe blade recommended by the blade manu-facturer for the type of material being cut.

Extension Cords An extension cord is fre-quently used to connect power to power tools.It should have a suitable wire size for the over-all cord length and the proper amperage ratingfor the tools with which it will be used(Table 1-1). This is necessary to prevent ex-cessive voltage drop, power loss, and possiblemotor damage. When tools are used outdoors,only extension cords labeled for outdoor useshould be used. For protection against poten-tial shock from an electrically-shorted powertool, a ground fault circuit interrupter (GFCI)-protected extension cord should be used.

LaddersExtension and step ladders (Figure 1-20) areoften needed to reach high places, such as roof-tops. They can be made of fiberglass,aluminum, or wood. Fiberglass and woodenladders are nonconductive, allowing them to beused when working around electricity. Alumi-num ladders are lightweight and easy to move,but should not be used where contact with elec-tricity is possible.

Ladders are rated by their total load capac-ity, which includes the combined weight of theuser, tools, and any materials bearing down onthe ladder rungs. Minimum load capacities usedfor installation work are 225 pounds (mediumduty), 250 pounds (heavy duty), and 300pounds (extra heavy duty).

t Figure 1-19.Portable Band Saw

t Table 1-1.Finding the Correct Extension Cord for the Job

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1.7ot21

1.21ot61

dednemmoceRdroCnoisnetxE)GWA(eziSeriW

52 81 81 61 41

05 81 61 41 21

57 61 41 21 01

001 41 21 01

t Figure 1-20.Extension and Step Ladders

STEP LADDER

EXTENSIONLADDER

INSTRUMENTS AND DEVICES 1

Common extension ladders range in sizefrom 16 to 40 feet (Table 1-2). Extension lad-ders are equipped with a rope and pulleysystem to help raise and lower the upper lad-der section. Self-locking rung latches attachedto one of the sections supports and securesthe raised section in place.

Step ladders are self-supporting, non-adjust-able ladders made in heights ranging from 4 to20 feet. WHEN USING A STEP LADDER,NEVER STAND ON THE TOP TWO STEPS.

Wooden ladders require proper mainte-nance. Moisture can be a problem, so theyshould be stored in a dry place to prevent rot.Never paint a wooden ladder. The paint canhide cracks, splinters, and dry rot. Use ofclear varnish or a preservative oil finish will pro-tect the wood without hiding these defects. Foradditional information about ladders andladder safety, refer to Section 2.

CUSTOMER RELATIONS FORINSTALLERSAppearances Count When people meet youfor the first time, they form their critical first im-pression of you based to a large extent on howyou look. Industry studies have consistentlyidentified the appearance of installers as a fac-tor that many customers consider important(Figure 1-21).

Ask yourself these questions: Do you get enough sleep and look alert? Do you practice good personal hygiene? Do you wear a neat, clean uniform and clean

shoes? Do you promptly identify yourself and show

an appropriate ID? Do you smile, display confidence, and polite

respect for the customer?If your answer to each question is Yes, con-

gratulations! You are well on your way toconsistently making the good first impressionyour company needs.

If you answered No to any of the questions,you have identified an area for improvementthat can change how people feel about you andyour company. Get to work on making that im-provement. You will be glad you did.

Before you head out to a job, look in the mir-ror and ask: Would someones spouse ormother want me in the house?

In addition, your vehicle is a traveling bill-board for your company (Figure 1-22). How itlooks and how you drive it can greatly influencethe publics impression of your company. Makethat positive impression on the road. Is your truck clean and in good repair? Are your driving habits courteous?

WARNING

CAUTION

t Table 1-2.Finding the Correct Extension Ladder for the Job

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mumixaMgnikroWthgieH)teeF(

61 31 9

02 71 31

42 12 71

82 52 12

23 92 52

63 23 82

04 53 13

t Figure 1-21.How You Look on the Job is Very Important

t Figure 1-22.Your Vehicle is a Traveling Billboard for YourCompany

ABC CO.HVAC INSTALLATION

INSTRUMENTS AND DEVICES 1

Treat Your Customers with Respect In away, admitting you into their home is a trustinggesture of faith by customers (Figure 1-23).They have faith that you will do no harm, andthat you will treat the premises and occupantswith respect. Do you agree? Think about thepeople you invite into your home.

Ask yourself these questions: Do you refrain from smoking? Do you remember to protect the work area? Do you carry rags and carefully clean up af-

ter yourself? Do you have drop cloths to protect floors and

carpets? Do you keep from tracking in dirt? Do you return the home to its original condi-

tion? (Replace covers, wipe off dirtyfingerprints, clean up drop cloths, etc.)

Good Work Habits Mark You as a SkilledProfessional As the number of homes withmore than one income has increased, the needfor installers to arrive on time has become morecritical than ever, since in these cases some-one may have to take time off from work to waitfor the installer. Be on time. Call if you are go-ing to be late (Figure 1-24). Show the customerthat you have consideration for their time.

It is a good idea to read the product installa-tion instructions before going on the job. Usinga wrong tool not only leaves behind poor re-sults, it tells your customer that you areunprofessional. Customers notice if you arrivewith a full set of tools, neatly packed. They no-tice your attitude, and whether it shows a goodwork ethic. They can see if you neatly repackyour tools when you finish the installation, too.It is part of how they judge you and your com-pany. It is also a large contributor to whetherthey call your company back for more work.

Review these questions. Any No answersindicate areas that need work. Are you on time? Do you arrive fully informed and prepared to

do the job? Are your tools a full set, neatly packed? Do you tackle the installation promptly? Do you avoid general social conversation

while working?

Customer Satisfaction Depends on whatYou Say as Well as what You Do Under-standing your customers needs is the first stepin achieving customer satisfaction (Figure 1-25).Imagine that you are the customer. What wouldyou like to know about a new installation? Youranswer is likely to include items your customerwould also want to know. Helpful Hint: Thinkof good communication with your customer asessential to understanding his/her needs.

When installers do not explain how thingswork and fail to give the customer a good over-

t Figure 1-23.Treat Your Customers with Respect...Begin withTheir Homes

t Figure 1-24.Good Work Habits Mark You as a SkilledProfessional

1

2

3

4

56

7

8

9

10

11 12

QUICK NOTENo company wants its employees usingalcohol, drugs, or profanity on the job,and no customer wants such people intheir home. On the job, always show thecustomer the kind of positive, profes-sional attitude and behavior you wouldexpect if YOU were the customer.

t Figure 1-25.Customer Satisfaction Depends on what You Sayas Well as what You Do

THE ORGANIZED INSTALLATION 1

view of how to use and maintain the product,they leave customers with unanswered ques-tions. Customers appreciate when you explainhow to operate and care for the product/sys-tem (Figure 1-26). Be brief, with no unnecessaryconversation.

Sometimes, learning your customers needscalls for using your powers of observation. Forexample, on a furnace job, a veteran installernoticed that his customer, a senior citizen, suf-fered from painful arthritis in her hands. Herealized that the simple task of changing thefilter would be difficult for her. So he suggestedan optional, inexpensive, external filter rack. Heexplained how easily the filter slides in and out.Without hesitation, she purchased the optionalrack. Weeks later, she was telling her friendsabout her helpful furnace man.

Many customers incorrectly assume that abrand-new, just-installed product can go foryears without maintenance attention. Sugges-tion: Explain that todays high-tech systems,like todays cars, need

regular maintenance.

t Figure 1-26.Customers Appreciate when You Explain how toOperate and Care for the Product/System

t Figure 1-27.Always Leave a Business Card or Put a Stickerwith Your Companys Phone Number on theEquipment

ABC Air Conditio

ning Inc.

Clean Air, USA

(522) 555-2948

Many top installers show their customers simple, self-help maintenance techniques that pro-long equipment life, such as how to change filters. In addition, they make sure the customer canset the thermostat, as well as explaining items unique to the product. For example, with heatpumps, the installer might explain how heat pumps work and tell why frost might form on the coil,and why the outdoor section must be kept clear of snow.

Top installers always leave the product literature packet with the customer because they knowthat with todays high-tech products, these instructions contain information that a servicing tech-nician might need someday. The owners manual also contains information that helps the ownerto better understand equipment operation and helps to prevent needless service calls. It is a goodidea to suggest to your customer that they keep the product literature, warranty, etc. in a safeplace.

Dealers who do large amounts of repeat business have trained their installers to make thingseasy for the customer. They make it easy to contact the dealer. They check back to make sure theinstallation is satisfactory.

Consider these loyalty-building questions: Do you leave a business card or put a sticker

with your companys phone number on theequipment (Figure 1-27) or leave a card withthe customer to keep near the phone?

Do you call the customer a day or two laterto ask if your product/system is working prop-erly?If you answered Yes, you are already mak-

ing opportunities for repeat business based onsatisfied customers. If you answered No, per-haps you should consider trying one or all ofthese proven business-building techniques.

Finally, remember that your customers ap-preciate a positive attitude. For example, it isalways best to be professional and avoid badmouthing older or competitive products. Like-wise, if for example, you are latebut it is notyour faultfocus on the positive, getting thejob done, rather than blaming someone else.Say something like: I understand how you feel.Im sorry. Please know that I will do my best tohave your new furnace installed as quickly as Ican.

SAFETY 2

SECTION 2

SAFETYtINTRODUCTIONThis section summarizes general safety information for persons involved with the installation,operation, and maintenance of heating, ventilating, and air conditioning (HVAC) equipment. Workingon HVAC systems means that you will encounter many potentially dangerous situationsinvolving:

SAFETY

ITS EVERYONES RESPONSIBILITY

Equipment containing liquids and gases under pressure Energized electrical equipment Contact with extremely hot and cold equipment surfaces Rotating machinery Contact with chemicals and hazardous materials Installation and repair work involving movement of heavy objects

SAFETY 2

PERSONAL SAFETYPersonal Safety EquipmentMany on-the-job injuries occur because work-ers do not use personal protective equipment(Figure 2-3). The exact type of personal safetyequipment depends on the potential hazardsinvolved and on the local and/or OccupationalSafety and Health Administration (OSHA) rulesthat apply to the job site. The most commonitems of personal safety equipment you will useas an HVAC technician are: Hard hat Protects head from hard blows

and falling objects. Safety glasses or goggles Protect eyes from flying objects or chemical splashes. Gloves Protect hands from cuts, scrapes, burns, and chemical or refrigerant spills. Safety shoes Protect feet from falling objects and prevent sharp objects from puncturing the

foot. Ear plugs/muffs Protect ears from exposure to high noise levels. Respirator Protects against breathing hazards or suffocation that might occur in the presence

of certain refrigerants or other gases. Safety harness/lanyard Prevents falls when working more than six feet above the ground or

near deep holes.To ensure that safety and protective equipment provides the intended protection, it should:

Be inspected regularly. Be cared for properly as directed by the manufacturers instructions. Be used properly, when needed, as directed by the manufacturers instructions. Never be altered or modified in any way.

t Figure 2-1.Always Learn New Skills Under the Supervisionof a Qualified Technician

t Figure 2-2.Read and Follow Specific Instructions in theManufacturers Literature

Only trained and qualified service personnelshould install or service HVAC equipment(Figure 2-1). Untrained personnel may performbasic maintenance tasks such as cleaning andreplacing filters with little supervision. However,unfamiliar tasks must be performed by (or un-der the supervision of) an experiencedtechnician.

The final responsibility for on-the-job safetyrests with you. Job and construction sites canbe hazardous places to work, but an aware-ness of the information provided in this sectionwill help you to avoid injuring yourself or dam-aging equipment. The safety instructions givenin this section and the remainder of this bookare general in nature and are not to be used asa substitute for the manufacturers instructions.No attempt should be made by anyone to in-stall, operate, adjust, repair, or dismantle anyequipment until the manufacturers specific in-structions have been read and are thoroughlyunderstood (Figure 2-2).

t Figure 2-3.HVAC Technician Wearing Safety Glasses andGloves

SAFETY 2

t Figure 2-4.Remove Watches and Other Jewelry BeforeInstalling or Servicing Equipment

Loose-Fitting Clothing and Jewelry HazardsRings or other jewelry, neckties, cloth gloves,or loose-fitting clothing must not be worn whenworking around equipment with rotating ormoving components. Motors that drive fans,compressors, and pumps are an example. Ifjewelry or clothing becomes caught in a motordrive pulley or coupling, severe injury could oc-cur. Rings or watches must not be worn whenworking around energized electrical equipment(Figure 2-4). Contact between the jewelry andan energized circuit may result in electric shock,injury, or death.LiftingLifting or moving heavy objects causes manyinjuries. Lift with your legs rather than your back,because your leg muscles are stronger. Whenlifting heavy objects, wear a back support beltor similar device for added protection from in-jury. Use the following procedure to lift heavyobjects (Figure 2-5). Move close to the object to be lifted. Squat down. Keep your back straight and

your chin tucked in. Position one foot behindthe other with the forward foot at the side ofthe object.

Grip the object from underneath using wholehands (not just fingertips), wrap your armsaround it, or use lifting handles when pro-vided.

Draw the object close to your body. Lift the object by slowly straightening your

legs. Keep the weight centered over your legsas much as possible. If possible, pick theobject up in the direction of travel to avoidtwisting your back or knees.

ELECTRICAL EQUIPMENTWhen working on electrical equipment, alwaysobserve the precautions in the service litera-ture, on tags, and on labels attached to orshipped with the unit. Perform all work to meetthe local and national electrical codes. For ad-ditional guidance, refer to the current issue ofthe National Electrical Code (NEC).

Electricity can be dangerous, but if you de-velop the proper safety attitude about workingwith it, you should have no problems. Workingon HVAC equipment involves working near ex-posed electrical components and/orconductors. This can expose you to the poten-tial hazards of electric shocks and burns.

QUICK NOTEIf an object is too heavy to liftcomfortably, ask for assistance or usea hoist or other lifting device.Remember, it is a lot easier to ask forhelp than it is to nurse an injuredback!

t Figure 2-5.How to Lift Safely

SAFETY 2

Electric ShockElectric shock happens when electrical currentflows through your body. It can damage yourheart by causing it to beat erratically or it mighteven cause it to stop, resulting in death. Highvoltage levels, such as 120 volts AC or 240 voltsAC, are always dangerous. However, even lowvoltages can be lethal (Figure 2-6).

Many technicians think of DC voltages as lowand relatively safe. In most cases, this is true.However, you can encounter high DC voltagein HVAC equipment that can be quite danger-ous. Exercise caution in these situations.

Usually, the high resistance presented by thehuman body will prevent harm from low volt-age. However, when skin is moist, or damagedas from a cut, the resistance of your body isgreatly reduced. Under such conditions, even40 volts or less can present a hazard. To pre-vent shocks, bodily contact between live (hot)circuits or a live circuit and ground must beavoided.

Circuit breakers with built-in ground fault cir-cuit interrupters (GFCI) may be used to protectHVAC equipment. These circuit breakers pro-tect the equipment from current overload. Theyalso help to protect individuals against shock.The GFCI device in the circuit breaker can de-tect a small current leak to ground, causing thecircuit breaker to trip and open the circuit. Sucha leak may not be detected by a conventionalcircuit breaker.

Portable, plug-in GFCI devices like the oneshown in Figure 2-7 are available that turn a stan-dard utility outlet receptacle into a GFCI-protectedcircuit. GFCI-protected extension cords are alsoavailable. Use them for added protection againstpotential shock from an electrically-shorted powertool.

Electrical shock can result from using defec-tive and/or improperly grounded power tools orfrom connecting power tools to improperlygrounded utility circuits. Use only approvedtools, equipment, and safety devices. Beforeuse, always make sure that all tools, equipment,and safety devices are working properly andare in good condition.

t Figure 2-6.Both High and Low Voltages can be Dangerous

HIGH VOLTAGE IS ALWAYS DANGEROUS. EVEN 40 VOLTS CAN BE LETHAL IF SKIN IS WET OR DAMAGED.

BE CAREFUL!

t Figure 2-7.Portable Ground Fault Circuit Interrupter (GFCI)Module

120V

TEST FAULT RESET

60Hz

When using tools or extension cords that have three-prong plugs, never remove or alter thegrounding prong on the three-prong plug in order to insert it into a two-prong electrical utilityoutlet. If you must connect equipment to a two-prong outlet, always do so using an approvedadapter with a green grounding lug. Make sure you connect the adapter grounding lug to a knownground such as a properly grounded outlet box. Since many outlet boxes are not properly grounded,always use a multimeter to verify that a good ground connection exists.

Electrical BurnsElectrical energy can pass for short distances through air. When it does, the arc and flash cancause burns, fires, and even explosions. Burns resulting from electrical arcs, such as in a shortcircuit to ground, can be extensive and deep. More serious burns can even result in amputation ofthe affected limb.

SAFETY 2

Lock Out/TagoutWhenever possible, shut off electrical power atthe disconnect or service entrance panel be-fore working on HVAC equipment. As shown inFigure 2-8, the disconnect or panel should belocked in the off position with a padlock andtagged (lock out/tagout) to make others awarethat service is in progress. Never assume thatthe equipment is dead. Use a meter toverify it.

If you must perform a test with power ap-plied, do not wear rings, watches, or other metaljewelry. Follow the safety guidelines listed be-low when you must work on equipment with thepower on: Have only one hand in the unit. Avoid working in wet or damp conditions. Avoid working in poor light or when tired. Unless required by the manufacturers ser-

vice procedure, do not bypass safety devicessuch as door interlock switches.

Make sure all grounds are connected prop-erly.

Use tools with insulated handles.

MECHANICAL EQUIPMENTRotating and Moving PartsEquipment should not be operated without thecoupling or belt guards installed, even if for onlya short interval such as when checking motorrotation.

When servicing equipment, guards shouldnot be removed from the equipment until it isdeenergized, locked out, and tagged(Figure 2-9). After removing electrical powerfrom a unit, never attempt to service it until allrotating and moving parts have come to a com-plete stop (Figure 2-10). Never try to stop acoasting motor or fan blade. If you grip the motorshaft, belt drive, pulley, or blades, the momen-tum can dismember or cut your hand severelyor pull your hand into the rotating mechanism.

Loose hardware thrown from a rotating com-ponent can be deadly. All set screws and otherattaching hardware must be tightened to speci-fications before starting a motor or other movingpart. It is a good practice to tighten all couplingbolts twice to be sure that none have been over-looked.

Sharp ObjectsContact with sharp metal edges and other ob-jects can cause injury. Be careful to avoid suchcontact when removing or replacing parts.

Hot and Cold Surfaces and WorkAreasContact with hot surfaces can burn your skinand leave permanent scars. These surfaces in-clude: furnace burners, heat exchangers, flues,electric heating elements, compressors, mo-tors, and refrigerant lines.

QUICK NOTEEven equipment that appears familiarmay have special model differencesfrom year to year. NEVER ASSUMEANYTHING! Always review and followthe manufacturers instructions wheninstalling or servicing any equipment.

t Figure 2-8.Lock Out/Tagout Equipment Disconnect Switch

DANGER

t Figure 2-9.Deenergize, Lock Out, and Tag Equipment BeforeRemoving Guards to Service Rotating Components

t Figure 2-10.Never Attempt Service Until all Rotating andMoving Parts have Stopped

GRILLE REMOVED

SAFETY 2

Refrigerant ContainersSee Figure 2-11. Low-pressure refrigerantsCFC-11, CFC-113, and HCFC-123 come instandard steel drums or cylinders. Their boil-ing point is close to, or slightly above, ambienttemperature. The pressure they exert on thecontainer is much less than that of medium andhigh-pressure refrigerants such as CFC-12,HCFC-22, HFC-134a, HFC-407C, HFC-410A,CFC-500, and CFC-502. These refrigerants areliquefied compressed gases. If improperlyhandled, the pressurized containers that holdthese refrigerants can burst or leak, causingdamage, injury, or even death.

Medium and high-pressure refrigerants comein either returnable or disposable metal con-tainers which vary in shape and size. Theyrange in capacity from about one pound of re-frigerant to 1,000 pounds or more. Do notreuse disposable (nonreturnable) contain-ers nor attempt to refill them. Disposablecontainers are made from common steel, whichcan rust. Rust weakens the container walls andseams so that they can no longer hold pres-sure and contain gases. Disposable cylindersshould be stored in dry locations to prevent rust-ing, and transported carefully to preventabrasion of their painted surfaces. Keep dis-posable containers in their original cartons asan added measure of protection.

CAUTION

Take care when soldering or brazing. High heat is present in the torch flame and the areasurrounding the parts being soldered or brazed. When soldering or brazing, keep a fire extin-guisher close by and know how to use it. Also, avoid wearing clothing made from manmadematerials such as polyester because these materials can turn into molten plastic should a flameaccidentally come in contact with the clothing.

Cold surfaces can be as harmful as hot ones. Contact with extremely cold metal surfaces canresult in frostbite or other injury. Frostbite can also result from prolonged exposure to cold whenworking outdoors or inside a freezer or cold storage room.

REFRIGERANT AND OTHER PRESSURIZED GASESExposure to RefrigerantsGloves and safety glasses must be worn when working with refrigerants. Avoid getting refrigeranton the skin or into your eyes. When accidentally released to the atmosphere, refrigerant cancause frostbite or burn the skin.

All refrigerants can cause suffocation if the concentration and time of exposure are great enough.Always provide adequate ventilation when working with refrigerants. Refrigerant vapor is invis-ible, usually has little or no odor, and is heavier than air. Therefore, be especially careful of lowplaces where it might accumulate.

Equipment rooms or other areas with large machines holding large amounts of refrigerant musthave alarm systems which detect small amounts of leakage and sound an alarm. Refrigerantsincrease dramatically in toxicity when exposed to an open flame or a hot surface. Self-containedbreathing apparatus must be available outside the equipment room or other area containing largeequipment in case leakage occurs and entry into the contaminated area becomes necessary.Some equipment rooms have a mechanical ventilation system to clear contaminated air from theroom.

t Figure 2-11.Refrigerant Containers

RETURNABLE

NOTE: RETURNABLE CONTAINERSARE REFILLABLE BUT THIS ISUSUALLY DONE AT THE FACTORY.

HFC-134aLight Blue

HFC-407CRust

HFC-410APink

HCFC-22Green

HCFC-123Grey

Color CodesCFC-11Orange

CFC-12White

CFC-113Dark Purple

CFC-500Yellow

CFC-502Purple

DISPOSABLE

RECOVERY CYLINDERSARE REFILLABLE

REFILLABLE

Refillable refrigerant containers must not be filled with more than 80% liquid. Never exceedtheir rated capacity in pounds as expressed by the net weight on the cylinder label. Be sure totake into account the container weight (tare lbs.) when estimating the net weight of refrigerant ina cylinder. Excess liquid in a cylinder causes hydrostatic pressure that can result in an explosion.Hydrostatic pressure increases rapidly with even small changes in temperature.

SAFETY 2

NEVER HEAT A CYLINDER WITH AN OPENFLAME OR PLACE AN ELECTRIC RESIS-TANCE HEATER IN DIRECT CONTACT WITHIT. If it is necessary to warm a cylinder, do itgradually and evenly with warm water(Figure 2-12). Do not exceed 125 F on anypart of the cylinder.

Always double check to be sure you are us-ing the proper refrigerant. The containers arecolor-coded and are also labeled to identify theircontents. Container labels also include prod-uct, safety, and warning information.

Technical bulletins and Material Safety DataSheets (MSDSs) available from the manufac-turers provide information important to yourhealth and safety. They describe the flamma-bility, toxicity, reactance, and health problemsthat could be caused by a particular refrigerantif spilled or incorrectly used.

In addition to the precautions describedabove, follow these rules when handling andusing refrigerant containers (Figure 2-13): Do not drop, dent, or abuse refrigerant con-

tainers. Do not tamper with safety devices. Always use a proper valve wrench to open

and close the valve. Replace the valve cap and hood cap to pro-

tect the cylinder valve when not in use orempty.

Secure containers in place to prevent themfrom becoming damaged from movingaround, especially in a van or truck. Strap orchain cylinders in an upright position.

Do not store containers where the tempera-ture can exceed the cylinder relief valvesettings.

Do not mix refrigerants.

Other Pressurized Gas HazardsNitrogen, oxygen, acetylene, and LP gases arecommonly used when installing or servicingHVAC equipment. These gases are com-pressed and shipped under medium to highpressures in cylinders. Because their use is socommon, technicians often get careless abouthandling them.

Nitrogen Nitrogen is supplied in cylinders atpressures of about 2,000 psi. These cylindersmust not be moved unless the protective capsare in place. Dropping a cylinder without thecap installed may result in breaking the valveoff the cylinder. This allows the pressure insideto escape, causing the cylinder to propel like arocket (Figure 2-14). Store nitrogen cylindersin an upright position and away from all flam-mable and combustible materials.

Because of the high pressure, a gauge-equipped pressure regulator must be used onthe nitrogen tank (Figure 2-15). In addition, arelief valve must be installed in the pressurefeed line to limit the pressure to a safe level foruse in the equipment being serviced.

NEVER CONNECT BOTH A REFRIGERANTCYLINDER AND A REGULATOR-EQUIPPEDNITROGEN CYLINDER TO THE EQUIPMENTAT THE SAME TIME BECAUSE THE HIGHERPRESSURE NITROGEN CAN CAUSE THE RE-FRIGERANT CYLINDER TO EXPLODE.

WARNING

WARNING

t Figure 2-12.Warming Cylinder with Warm Water

WARM WATER

DO NOT EXCEED 125 F ON ANYPART OF THE CYLINDER

t Figure 2-13.Refrigerant Container Safety

STRAP ORCHAIN IN ANUPRIGHT POSITION

DO NOT DROP, DENT, OR ABUSE CONTAINERS ALWAYS USE THE PROPER VALVE WRENCH PROTECT AGAINST HIGH TEMPERATURES

REPLACEVALVE CAP ORHOOD CAPWHEN NOT IN USE

t Figure 2-15.Gauge-Equipped Pressure Regulator Used withNitrogen

TESTINGPRESSUREGAUGE

PRESSURERELIEFVALVE

HANDVALVE

CONNECTEDTO GAUGEMANIFOLDSET

PRESSUREREGULATOR

CYLINDERSAFETYVALVE

CYLINDERPRESSUREGAUGE

NITROGENCYLINDER

t Figure 2-14.A Compressed Gas Cylinder Becomes a Dangerous Projectile if the Valve is Broken Off

SAFETY 2

t Figure 2-16.Oxygen Mixed with Oil can Cause an Explosion

OXYGEN

Oxygen Like nitrogen, oxygen is supplied incylinders at pressures of about 2,000 psi. Whenhandling oxygen cylinders, follow the same pre-cautions as for handling nitrogen cylinders.

Oxygen can cause ignition even when noflame or spark is present, especially when itcomes into contact with oil or grease(Figure 2-16). OXYGEN MUST NEVER BEUSED TO PRESSURIZE A SYSTEM SINCE ANEXPLOSION HAZARD EXISTS WHEN OILAND OXYGEN ARE MIXED. Never handle oxy-gen cylinders with oily hands or gloves. Keepoil and grease away from the cylinders and cyl-inder attachments or valves. Store oxygen inan upright position and away from all flammableand combustible materials, including gases likeacetylene. There should be a minimum of 20feet separating oxygen cylinders from fuel cyl-inders in storage, or they must be separated bya 1/2-hour minimum fire-rated wall that is at leastfive feet high. Never use an oxygen regulatorfor any other gas and never use a regulator foroxygen that has been used for other service.

Acetylene Acetylene cylinders are pressur-ized at about 250 psi. Even with its much lowerpressure, acetylene should be handled with thesame precautions as nitrogen and oxygen be-cause acetylene is flammable. Apressure-reducing regulator must be used andset at a pressure of not more than 15 psig.ACETYLENE BECOMES UNSTABLE ANDVOLATILE ABOVE 15 PSIG. The valve wrenchshould be left in position on open acetylenevalves. This enables quick closing in an emer-gency. It is a good practice to open theacetylene valve as little as possible, but nevermore than 1-1/4 turns. Also, be sure not to usea torch tip that will exceed the flow capacity ofthe cylinder type (MC or B) being used. Use oftoo large a tip can result in excess flow fromthe cylinder, causing the tank absorbent (ac-etone) to be drawn from the cylinder and flowinto the regulator, hose, and torch. This can oc-cur when small multiple-flame (rosebud) tips areused with an MC cylinder or large rosebud tipsare used with a B cylinder.

Liquid Petroleum (LP) LP gases such aspropane and butane are usually pressurized atless than 300 psi and should be handled withthe same precautions as nitrogen and oxygen.LP gas is heavier than air and explosive. It isnormally used as a fuel gas in furnaces. As withthe other gases discussed, a pressure-reduc-ing regulator must be used. Gloves and safetyglasses must be worn when working with LPgas. When accidentally released to the atmo-sphere, LP gas can cause frostbite or burn theskin. Do not use pure LP gas in a furnace setup for natural gas because an unsafe condi-tion will be created. If using LP gas for soldering,be sure not to turn the cylinder upside down.This allows liquid fuel to flow into the torch andmay cause an explosion.

Figure 2-17 summarizes the cylinder pres-sures of common gases.

t Figure 2-17.Cylinder Pressures of Common Gases

GAS PRESSURE NITROGEN 2,000 psi OXYGEN 2,000 psi ACETYLENE 250 psi LIQUID PETROLEUM

SAFETY 2

GAS AND OIL HEATING EQUIPMENTWhen working on heating equipment, always observe the precautions in the service literature, ontags, and on labels attached to or shipped with the unit. Perform all work to meet the local and nationalgas or oil codes. For additional guidance, refer to the current issues of the National Fuel Gas Code(NFPA No. 54/ANSI Z223.1) and/or the National Fire Protection Association Code.Gas LeaksHeating equipment can be hazardous due to the combustible fuels involved. Natural gas can bedangerous because it can displace oxygen in the air and, if it accumulates, can be explosive. LPgases are heavier than air and can collect in low places to form pockets of highly explosive gas.All fuel gases have odorants added to make leak detection easier. If a leak occurs that causesgas to collect inside a building, the following immediate actions must be taken:

t Figure 2-18.Never Use an Open Flame to Check for Leaks

t Figure 2-19.Always Clean Up Oil Leaks Immediately

ABSORBANT

Clear the area of all occupants. Do not re-enter until it is known to be safe.

Notify the local gas utility. Shut off the supply of gas. Use every reasonable means to eliminate

sources of ignition. Do not operate electricswitches. If lights are already turned on, donot turn them off. If turned off, leave themoff.

Ventilate the area by opening windows anddoors.

Never use matches, candles, a flame, orother sources of ignition to check for gasleaks. Use a soap and water solution(Figure 2-18).

Use only a battery-operated flashlight or ap-proved safety lamp when searching for theleak.

Oil LeaksFuel oil on the floor or an accumulation in thefurnace combustion chamber are usually signsof a leak. Leaking fuel oil in the presence of airand an ignition source can result in a fire. As aprecaution to prevent leaks, compression fit-tings should not be used to pipe an oil-burningsystem. Absorb and clean any oil spilled on thefloor with rags, absorbant, a suction pump, shopvacuum, etc. (Figure 2-19).

Care should be taken not to start a furnace ifany oil has accumulated in the combustionchamber. If oil has accumulated, shut off the oilvalves and vent the chamber. Turn off the elec-trical power. Remove the oil with a suctionpump.

If the puddle of accumulated oil is ignited, itwill burn intensely. You may not be able to ex-tinguish the fire; it will have to burn itself out. Ifthis happens: Notify the fire department. Shut off the burner motor but allow the fur-

nace fan to run to help dissipate the heat. Shut off the air shutter to reduce the air to

the burner. Let the fire burn itself out with reduced air.

SAFETY 2

Standing Leak Test and PurgingOXYGEN MUST NEVER BE USED TO LEAKTEST OR PURGE A GAS OR OIL FURNACEPIPING SYSTEM SINCE AN EXPLOSIONHAZARD EXISTS WHEN OIL AND OXYGENARE MIXED.

After the leak test of a gas furnace is com-pleted, the gas trapped in the system shouldbe purged in a well-ventilated area to rid thesystem of air or other gases. When doing so,be careful not to purge the gas where it will col-lect in the furnace combustion chamber. Afterpurging, but before operating the unit, it is agood practice to wait at least 5 minutes to al-low any accumulated gas to dissipate. Whenlighting the furnace pilot, never stand in front ofor look into the combustion chamber.

Incomplete CombustionOnly experienced technicians should make fur-nace combustion adjustments and then only asdirected by the manufacturers instructions.Fuel and combustion air must be mixed safely.Incorrect gas or oil pressure, wrong orifice typeor size, or improper burner position or adjust-ment can result in incomplete combustion. Thiscauses the furnace to produce aldehydes, soot,and carbon monoxide (CO) gas (Figure 2-20).Carbon monoxide gas is deadly. Prolongedbreathing of carbon monoxide can result in sick-ness or death. An inadequate supply of primaryor secondary air to the burners caused by somerestriction to airflow can cause flame rollout,possibly starting a fire.

Other Gas and Oil Heating PrecautionsIn addition to the safety precautions discussedabove, observe the following guidelines whenservicing gas and oil heating equipment: Gas, oil, and electricity should be turned on

only when it is necessary to check the op-eration of a component or the furnace. At allother times during equipment maintenance,they should be turned off.

t Figure 2-20.Incomplete Combustion

WARNING

INCOMPLETE COMBUSTION CAN PRODUCE

CARBONMONOXIDE ALDEHYDES SOOT

Gas and oil furnaces should not be installed where flammable vapors or combustible materialsexist.

Never operate a furnace with a corroded, pitted, or cracked heat exchanger. Leaking combus-tion gases may cause sickness or death.

Do not jumper limit switches or other safety devices. These devices protect the furnace, build-ing, and occupants from fire or damage caused by malfunctions that result in overheating.

Gas and oil furnaces must be properly vented to avoid leaking carbon monoxide in the heatedarea should the furnace combustion be incomplete. Also, any vent gases that leak into theheated area will reduce the oxygen level.

Be extremely cautious when working around energized pilot lights, electronic spark igniters,and oil furnace ignition circuits. The control transformer secondary voltage and electrodes ofsome ignition devices operate in the range of about 10,000 to 20,000 volts.

SAFETY 2

INSTALLATION TOOL USE PRECAUTIONSInstallation work requires that you take precautions to work safely with power tools and otherinstallation equipment while performing the various tasks.

Power ToolsThe general safety procedures used when working with power tools are basically the same re-gardless of the tool being used. Safety begins by dressing properly and wearing safety glassesand face and/or dust masks, if appropriate. Loose clothing and jewelry must be removed becausethey can become caught in the moving parts of tools or equipment. Safety-type non-skid footwearmust be worn. Protective hair coverings must be worn to prevent long hair from becoming caughtin moving parts.

t Figure 2-21.Inspect Tools Before Using

t Figure 2-22.Use of the Right Tool is Safer

ALL PROTECTIVE GUARDS ATTACHED AND WORKING

CORRECT ALIGNMENT AND NO BINDING OF MOVING PARTS

NO

YES

t Figure 2-23.Horseplay can be Dangerous

Before using a tool, inspect and check thatthe guards are properly attached and make surethat they operate properly and will work as in-tended (Figure 2-21). Check for alignment and/or binding of moving parts, and any other con-dition that may affect operation. Always repairor replace any damaged guard or other dam-aged part before using a tool.

Use the right tool (Figure 2-22). Do not use alight-duty tool to do the job of a heavy-duty tool,or use one for a purpose for which it was notintended. The right tool will do a better job andbe safer to use.

NEVER OPERATE PORTABLE ELECTRICTOOLS IN EXPLOSIVE ATMOSPHERESSINCE THE MOTORS IN THESE TOOLSNORMALLY GENERATE SPARKS WHICHCAN IGNITE ANY FUMES. Keep work areasclean because clutter invites injury. Customersand visitors should be prohibited from the im-mediate work area to prevent accidents. Also,dangerous practical jokes and horseplay mustbe avoided because they can result in accidents(Figure 2-23).

In addition to the precautions previously de-scribed, also follow these rules: Always operate the tool as directed in the

manufacturers instructions. Never carry a tool by its cord or yank the cord

to disconnect it from a receptacle. Keep thecord away from heat, oil, and sharp edges.

Stay alert. Watch what you are doing anduse common sense. Do not operate a toolwhen you are tired.

Use clamps or a vise to hold the work. It issafer and it frees both hands to operate thetool (Figure 2-24).

Make sure to remove adjusting keys andwrenches before turning the tool on.

Disconnect tools when not in use, before ser-vicing, and when changing blades, bits, andcutters.

Prevent unintentional starting. Do not carrytools plugged into electrical outlets with yourfinger on the switch. Be sure the switch isset to the OFF position before plugging a toolinto an outlet.

Avoid overreaching by keeping proper foot-ing and balance at all times while using thetool.

When using an extension cord outdoors, al-ways use one approved for outdoor use.

WARNING

SAFETY 2

Air-powered tools are sometimes used instead of electrical-powered tools for drilling and cut-ting jobs. When using air-powered tools, follow the same general safety practices as would beused with the similar electrical tool. Before disconnecting the air supply hose from a tool, makesure to first shut off the air supply and use the tool trigger to bleed off and vent the air in the hose.

Powder-actuated tools that use a gunpowder cartridge are sometimes used to drive fastenersinto steel or concrete. Because of the potential danger that the misuse of these tools may cause,only trained and certified employees are permitted to operate these tools. Refer to Section 3 fordetailed information about powder-actuated tools, including any safety-related factors.

t Figure 2-25.Raising the Extension Ladder

t Figure 2-24.Clamp Work and Use a Two-Hand Grip

QUICK NOTEOnly trained and certified personsmay operate explosive powder-activated tools. Certification isestablished by the possession of anaccredited operators card.

Ladders and ScaffoldingBefore use, ladders should always be inspectedto make sure the rails, rungs, safety latches,and feet are not missing, broken, damaged, orloose. It is important that both straight and ex-tension ladders be raised and placed at theproper angle before climbing them(Figure 2-25).

Once upright, raise the extended section tothe desired height, making sure that the safetylatches are engaged. Position the bottom of theladder so that the horizontal distance betweenthe ladders feet and the wall is about 1/4 theladders vertical height or working length, whichis the length of the ladder between the foot andthe top support (Figure 2-26). Both of theladders feet should be an equal distance fromthe wall, so the ladder does not rock. If you aregoing to step off the ladder onto a platform orroof, the top of the ladder should extend at least3 feet beyond the support point.

Once the ladder is in position, fasten and/orblock it securely at the top and bottom. Stepladders should always be opened and set levelon all four feet, with the spreaders locked inplace (Figure 2-27). Never use a step ladderlike a straight ladder or stand on the top twosteps. For balance, lean your body into the lad-der. When you can no longer reach your workcomfortably, get down and move the ladder.

Falls account for most of the accidents thatoccur when working on ladders. To prevent fallsand other accidents, follow these precautions: Never use a damaged ladder or one with bro-

ken or missing rungs or steps. Any suchladder should be removed from service.

Barricade or put guards around a ladder thatis erected in doorways, passageways, or anylocation where it can be jarred or knockedover by others.

When climbing up a ladder, keep both handson the rails and your bodys weight centeredbetween the rails.

Face the ladder at all times when workingfrom it. If it is necessary to work backwards,use a harness or safety belt with a lanyard.

Do not carry tools or materials in your handswhile climbing a ladder. Haul them up or havesomeone hand them to you.

Never try to move a ladder while standingon it.

Do not use metal ladders near electric linesor services.

Never use a ladder as a scaffold by placingit horizontally and standing on it. Ladders aremade for vertical use only.

t Figure 2-26.Proper Positioning of an Extension Ladder

FASTENSECURELY

FASTEN SECURELY

VERTICALHEIGHT

3 FEETMINIMUM

1/4 VERTICAL HEIGHT

SAFETY 2

Metal scaffolds may sometimes be used in-stead of ladders. When erected level and plumbon a firm base, scaffolds provide a safe, se-cure elevated work platform. A green, red, oryellow tag should be attached to any scaffoldthat is assembled and erected to alert users ofits current mechanical and/or safety condition(Figure 2-28). Do not rely solely on the tag. In-spect all parts of a scaffold before each use.Handrails, toeboards, and decking must all bein place, all wheels must be locked on mov-able models, and all locking pins must beinstalled. Other precautions that must be takenwhen working on scaffolds are: Never exceed the weight limit of the scaf-

fold. This stated weight limit includes the totalweight of people, tools, equipment, and ma-terials.

Do not climb on or work from any scaffoldrailing or brace members. Use a ladder toget on the scaffold.

Keep a minimum of 15 feet separation be-tween the scaffold and any energizedelectrical lines or equipment.

Remove or secure all tools and materials ona scaffolds deck before moving the scaffold.Do not ride on the scaffold when it is beingmoved. Watch overhead clearances whenmoving.

If people can pass under the scaffold, screenthe space between the toeboard and top railto prevent tools and materials from falling offthe work platform.

Do not use scaffold railings or braces for rig-ging.

QUICK NOTE To ensure extension ladder strengthand your safety, keep a minimumoverlap between extended sections of3 feet for 16- to 36-foot ladders; 4 feetfor 36- to 48-foot ladders; and 5 feetfor 48- to 60-foot ladders.

t Figure 2-27.Position Step Ladder so Feet are Level on Floorand Braces are Locked

PUSH SPREADERSDOWN TO LOCK

t Figure 2-28.Check Tags on Assembled Scaffolds

DO NOT USETHIS SCAFFOLD

KEEP OFF

THIS SCAFFOLD IS BEING

ERECTED OR TAKEN DOWN

ONLY AUTHORIZEDEMPLOYEES

USING REQUIRED

PERSONAL PROTECTIVE

EQUIPMENT MAY WORK

ON THIS SCAFFOLDDATE:CARPENTER/ERECTION CRAFT FOREMAN

THIS SCAFFOLD DOES

NOT MEET

FEDERAL/STATE OSHASPECIFICATIONS

EMPLOYEES WORKINGFROM THIS SCAFFOLDMUST WEAR AND USE

APPROVED FALL PROTECTION

DATE:

CARPENTER/ERECTION CRAFT FOREMAN

THIS SCAFFO

LD

HAS BEEN

ERRECTED

TO MEET

FEDERAL/S

TATE

OSHA STAN

DARDS

AND IS SAF

E FOR

ALL CRAFT

WORK

DO NOT ALT

ER

DATE:

CARPENTER

/ERECTION C

RAFT FORE

MAN

GREEN YELLOW RED

TAGS SHOW MECHANICALAND SAFETY CONDITION

QUICK NOTE SCAFFOLD TAGS Green Tag Meets OSHA standards and is safe to use. Yellow Tag Scaffold does not meet all OSHA standards. It can be used; however, it is mandatory

that the person using it wear and properly use a safety harness and lanyard fall protection gear. Red Tag Keep off, the scaffold is damaged and unsafe, or in the process of either being erected

or taken down.

SAFETY 2

Soldering and Brazing EquipmentSoldering and brazing tasks normally involve the use of torches and accessories. The generalsafety precautions described earlier in this section about the use and handling of pressurizedgases apply. The precautions given in Figure 2-38 at the end of this section also apply. Proce-dures for soldering and brazing, including safety factors, are provided in Section 5. The materialin both this section and Section 5 should be reviewed and understood before you attempt anysoldering and/or brazing tasks. Other precautions to take when using soldering and brazing equip-ment are:

t Figure 2-29.Use a Fire Retardant Shield to Protect the Surrounding Area and Components from Flame and Spark Damage

To extinguish any fires, always keep a fireextinguisher within 25 feet of the work area.

Use flame retardant shields to help protectadjacent areas from flame and spark dam-age (Figure 2-29).

Wear protective gloves and use proper toolsto handle hot work. When brazing, weargoggles having an ANSI Z87.1 standardshade No. 4 or 5 lens.

Do not point the torch flame towards yourface or body or at other persons.

Avoid getting flux on the skin or in the eyes.Avoid inhaling soldering or brazing fumes.

Rigging EquipmentRigging involves the movement of equipmentand materials using ropes, slings, cables, roll-ers, hoists, and cranes. It is necessary that yoube aware of rigging techniques and safety fac-tors in order to prevent injury or damage to theequipment. For safe rigging, the tools andequipment used must be in good condition andof the required strength to handle the load(Figure 2-30).

Always refer to the manufacturers literatureto find the maximum weight of the equipment.Always follow all warnings and cautions aboutrigging and mounting of the equipment givenin the installation instructions and/or on instruc-tion labels on the equipment.

General safety precautions for the use andhandling of rigging equipment and loads areshown in Figure 2-40 at the back of this sec-tion. The material in both this section andSection 4 should be reviewed and understoodbefore attempting any rigging tasks.

QUICK NOTE

On sunny days, it may be difficult tosee the torchs flame.

On windy days, the torchs heat maybe carried towards you or to areasnot intended to be heated.

t Figure 2-30.Rigging Tools and Equipment Must be in GoodCondition and of the Strength Required toHandle the Load

SAFETY 2

EXTREME HOT AND COLDWEATHER PRECAUTIONSPerforming service or installation work outdoorsin extreme heat or cold requires that appropri-ate precautions be taken to prevent bodily injuryor illness.

Hot Weather PrecautionsHeat stroke can result from heavy exertion inhigh temperature and/or high humidity condi-tions. When working in these conditions, dressin loose, cool cotton clothing and take periodicbreaks to avoid overexerting yourself.

Heat stroke can be life-threatening becausethe bodys heat-regulating mechanism stopsworking. This can cause convulsions, uncon-sciousness, and even death if the body is notcooled quickly. If heat stroke occurs, do notdelay getting immediate medical attentionfor the affected person. To help reduce thebody temperature, move the person to a coolplace and remove as much clothing as possible.Douse the person with water or wrap him orher in a wet sheet.

Heat exhaustion and heat cramps happenwhen body fluids are lost through heavy sweat-ing, but the sweat cannot evaporate fast enoughto cool the body. To help reduce body tempera-ture, the affected person should be moved to acool place and clothing removed. Crampedmuscles can also be gently stretched and mas-saged. Give sips of salt water and getimmediate medical attention.

Cold Weather PrecautionsWorking in extremely cold weather requires thatyou dress adequately to protect against thecold. Dress in layers to allow you to adjust tochanging temperature conditions. Cotton orlightweight wool should be worn next to the skinwith wool layers over the undergarments. Outergarments should be waterproof and wind re-sistant. A hat with ear protection prevents heatloss from the head. Waterproof boots shouldbe worn in wet or snowy weather.

The effects of hypothermia (low body tem-perature) are gradual, and often go unnoticeduntil it is too late. It is recommended that abuddy system be used when working in extremecold. If working alone, let someone know whereyou will be and what time you expect to return.Get immediate medical attention for hypo-thermia. Move the person indoors and removeany wet clothing. If the person is conscious, givehot liquids and/or a hot bath to speed up thewarming process.

The ears, nose, hands, and feet can be af-fected by frostbite. If affected by frostbite,cover the frostbitten area to protect it andget immediate medical attention.

QUICK NOTE

SYMPTOMS OF HEAT STROKE Sudden onset Dry, hot, and flushed skin Dilated pupils Loss of consciousness Fast pulse Deep breathing at first, later shallow

or almost absent Muscle twitching Body temperature 105 F or higher

SYMPTOMS OF HEAT EXHAUSTION/HEAT CRAMPS Weak pulse Rapid and usually shallow breathing General weakness Pale, clammy skin Heavy sweating Dizziness, disorientation Slightly above normal body

temperature Painful muscle cramps

CAUTION

QUICK NOTE

SYMPTOMS AND PROGRESSION OFHYPOTHERMIA Shivering Slurred speech Mental confusion Drowsiness and weakness Glassy stare Respiration and pulse rate become

slower and slower Extremities freeze Death

SYMPTOMS AND PROGRESSION OFFROSTBITE Exposed skin reddens Skin takes on a gray or blotchy

appearance, especially at the earlobes, cheeks, and tip of the nose

Exposed skin surface becomesnumb

All sensation is lost and the skinbecomes white

CAUTION

CAUTION

SAFETY 2

GENERAL SAFETYAWARENESSHazard Communication StandardThe work place contains many hazards thatneed to be recognized and respected(Figure 2-31). The OSHA Hazard Communica-tion Standard (HazCom), commonly called theRight To Know requirement, affects everyworker. It addresses the workers right to knowthe specifics about any major environmental,chemical, biological, physical, or radiation haz-ards that may exist at the job site. It requiresthat a Material Safety Data Sheet (MSDS) ac-company every shipment of a hazardouschemical or substance and be available to youon the job site. It is your responsibility to: Read the Material Safety Data Sheets that

pertain to your work and work location toidentify any physical and health hazards.

Know and practice the actions necessary toprotect yourself and others from any hazards.Know the actions to take in an emergency.

Spot and report potential hazards on the job.

t Figure 2-31.Safety Depends on Your Awareness

MSDS

Know: MSDS's

Safety Practices

Emergency Procedures

How to Spot and Report Hazards

Confined SpacesInstallation and service work is not always done outside or in open areas. Much of it takes placein confined spaces. A confined space is any area that cannot be easily ventilated, such as abasement equipment room. Confined spaces can contain hazardous gases and/or fluids whenthe equipment is operating. Work you are doing, such as soldering and brazing, may introducehazardous fumes into the space. To ensure safety, special precautions are needed before enter-ing, and while working in, a confined space:

t Figure 2-32.Use Respiratory Equipment when Required

Have one person inside and one outside theconfined space. Voice or visual contactshould be maintained to identify the need foraid in case of an emergency.

Keep rescue equipment ready for an emer-gency.

Use respiratory protection equipment whenrequired (Figure 2-32). If in doubt, have airsample readings taken to check for low lev-els of oxygen and/or explosive gases.

Use only approved electrical tools, extensioncords, etc.

Hazardous Waste ManagementWaste such as used oil or refrigerant, chlorinated solvents, chemical treatment solutions, acids,etc. may contain toxic components that require special handling and proper disposal at an EPA-approved waste management facility. When working with hazardous waste: Be knowledgeable about the use of chemicals from the Material Safety Data Sheets and follow

the manufacturers instructions. Wear the proper protective equipment, such as safety goggles, rubber gloves, and aprons

when handling or containing hazardous waste. Use only EPA/DOT-approved containers for storage, transport, and disposal of hazardous

wastes. Make sure the content of the container is identified by the proper EPA/DOT labelcontaining all the required information.

SAFETY 2

t Figure 2-33.Typical Terms Used to Prioritize Safety Hazards

SUMMARY OF DANGERS,WARNINGS, CAUTIONS, ANDSAFETY INSTRUCTIONSThe terms DANGER, WARNING, and CAU-TION have specific meanings that have beendesignated by the American National StandardsInstitute (ANSI) to clearly identify the degree ofhazard. The definitions and color coding shownin Figure 2-33 are typical of those used in theHVAC industry to prioritize safety hazards.

Figures 2-34 through 2-41 shown in the re-mainder of this section are typical examples ofsafety precautions and information you will seeboth in equipment manufacturers Installation,Start-Up, and Service literature and on equip-ment warning labels.

To avoid hazards and servicing mistakes, itis a good practice to always review a proce-dure before doing it. This review makes youaware of, and able to handle, all of the impor-tant safety conditions before you start.

DANGERThere is an immediate hazard which WILL result in severepersonal injury or death.

WARNING

Hazards or unsafe conditions which COULD result in

severe personal injury or death.

CAUTION

Potential hazards or unsafe practices which COULD result

in minor personal injury or product or property damage.

!

!

!

RED WITHWHITE LETTERS

ORANGE WITHBLACK LETTERS

YELLOW WITHBLACK LETTERS

SAFETY 2

BE AWARE that certain automatic start arrangements can engage the starter.Open the disconnect and lock it out ahead of the starter in addition to shutting offthe machine or pump.DO NOT bypass, block interlocks, or remove a lockout/tagout that is in placeunless it is yours.MINOR SHOCKS can surprise you. While the shock itself would probably notbe injurious, a resulting fall could be.DO NOT check a circuit until you are sure that the power is off in any adjacentcircuit.

CAUTION!

t Figure 2-34.Electrical Equipment Precautions

DO NOT attempt to check voltage supplies until you know the proper proceduresand have the proper equipment. SEVERE PERSONAL INJURY CAN RESULT.Consult your power company for specific instructions and obtain their serviceswhen necessary.DO NOT attempt to take measurements on high-voltage systems (600 volts orover) with hand-held instruments. Always use current and potential transformersto take high-voltage measurements.DO NOT take measurements or make continuity checks on a compressor until youare sure that ALL POWER IS TURNED OFF TO THE UNIT OR SYSTEM,INCLUDING THE CRANKCASE HEATERS. When taking voltage, current, orcontinuity measurements on a hermetic or semi-hermetic compressor in a pressurizedsystem, always take measurements at terminal boards and test points away fromthe compressor, rather than at the compressor. If the compressor terminals aredamaged and the system is pressurized, disturbing them to take measurementscould cause them to blow out, causing injury. Once a system has been evacuated andis no longer under pressure, measurements can be taken at the compressor. Checkthe lockout and tagout of both electrical components and the compression system.

DANGER!

WARNINGDO NOT work on high-voltage equipment unless you are an experienced HVACtechnician qualified to maintain electrical equipment or a qualified electrician.GROUND all electrical equipment.USE a ground fault circuit interrupter with power hand tools.DO NOT work on electrical components, including control panels, switches, starters,or heaters until you are sure that ALL POWER IS OFF and no residual voltage canleak from capacitors or solid-state components.LOCKOUT AND TAGOUT electrical circuits before working on them. IF WORKIS INTERRUPTED, confirm that the circuits are deenergized before resuming work.DO NOT remove terminal box covers while machine or compressor is running.DO NOT tighten any connection on a terminal board until the main disconnectswitch is in the OFF position and locked out.DO NOT attempt to stop a machine by opening an isolating knife switch. Highintensity arcing can occur and cause serious injury.NEVER USE an ohmmeter in any energized circuit. Destruction of the meter couldresult in personal injury.NEVER apply voltage to or operate a compressor when there is a vacuum in thesystem. This can cause the compressor terminals to fail due to internal arcing which,in turn, can result in severe personal injury.NEVER energize a compressor until the discharge service valve is open to thesystem. Failure to do so can result in excessive pressure buildup.DO NOT exceed the manufacturers torque specifications when making electricalconnections. Terminal bolts could snap and propel from the terminal block.

!

SAFETY 2

t Figure 2-35.Gas and Oil Heating Equipment Precautions

Improper installation, adjustment, alteration, service, maintenance, or use ofequipment can cause carbon monoxide poisoning, explosion, fire, electrical shock,or other conditions which may cause personal injury or property damage. Consulta qualified installer, service agency, local gas supplier, or your distributor or branchfor information or assistance. The qualified installer or agency must use onlyfactory-authorized and listed kits or accessories when modifying products. Failureto follow this warning could result in electric shock, fire, personal injury, or death.When a furnace is installed in a residential garage, it must be installed so thatburners and ignition sources are located a minimum of 18 in. above the floor. Thefurnace must be located or protected to avoid physical damage by vehicles. Whena furnace is installed in a public garage, airplane hangar, or other building havinga hazardous atmosphere, the unit must be installed in accordance with therequirements of the National Fire Protection Association Inc.NEVER USE OXYGEN OR COMPRESSED AIR to leak test or purge gas or oilfurnace piping systems since an EXPLOSION HAZARD exists when oil andoxygen are mixed. Follow the manufacturers recommendations for leak testingor purging.NEVER use matches, candles, flame, or other sources of ignition for the purposeof leak detection. Use a battery-operated flashlight or approved safety lamp whensearching for the source of the leak. For gas leaks, use a soap-and-water solutionto check for leakage. Failure to follow this warning could result in fire, explosion,personal injury, or death.NEVER purge a gas line into a combustion chamber. Failure to follow this warningcould result in fire, explosion, personal injury, or death.Use the proper length of pipe to avoid stress on the gas control manifold. Failureto follow this warning could result in a gas leak resulting in fire, explosion, personalinjury, or death.

WARNING!

SAFETY 2

t Figure 2-36.Leak Testing and Pressure Testing Precautions

NEVER USE OXYGEN to leak test, purge lines, or pressure test a machine.Nitrogen is recommended for these purposes. Always use a gauge-equippedregulator on the nitrogen cylinder and verify that the gauge has been recentlychecked and calibrated.

The full pressure of a nitrogen cylinder can cause a refrigerant cylinderto rupture violently. Therefore, when using nitrogen and a refrigeranttrace for leak testing, always put the refrigerant in first. Then valve offand remove the refrigerant cylinder before connecting and adding theregulated nitrogen.

NEVER EXCEED the specified field leak test pressures. Verify the allowable fieldtest pressure by checking the instruction literature.

Do not allow the full cylinder pressure to enter a pressurizing line.Valve off and disconnect the nitrogen cylinder when the recommendedtest pressure is attained. Do not rely on the shutoff valve or pressureregulator.Do not pressure test any vessel at its design pressure (found on theequipment nameplate). Testing at these pressures must be done in aspecial enclosure or by using a hydraulic fluid under the direction ofthe manufacturer.Do not confuse water (brine) side test pressures with refrigerant sidetest pressures.

HEAVY CONCENTRATIONS of nitrogen within a confined space or area candisplace enough oxygen in the work area air to cause suffocation.DO NOT enter any vessel or confined space immediately after the use of significantamounts of nitrogen without the protection of SCBA or first testing the oxygenlevel. Utilization of respiratory protection should not be needed if adequateventilation of the space is allowed to occur prior to entry and the oxygen level hasbeen tested and is above 19.5 percent.

DANGER!

SAFETY 2

t Figure 2-37.Mechanical Equipment Precautions

DO NOT remove coupling (or belt) guards to work on a machine until all rotatingparts have come to a complete halt.MACHINES MUST BE locked out and tagged out regardless of the type of energypowering the equipment.NEVER ENTER an enclosed fan cabinet or reach into a unit while the fan is running.NEVER use a torch to remove a compressor or component from the refrigerantcircuit. The oil could ignite and cause a fire. Use a pipe cutter and follow correctprocedures when cutting refrigerant lines.

DANGER!

WARNINGNEVER OPERATE an open-drive machine, pumpout unit, or other equipmentwithout coupling (or belt) guards in place. This warning applies even to short runssuch as a motor rotation check. Serious injury can result from contact with movingparts.NEVER loosen any head or cover bolts when the compressor is open to the systemor when it is under pressure. Make sure the internal pressure is at 0 to 2 psig beforeany bolts are loosened to prevent propulsion of compressor parts.DO NOT attempt to remove fittings and covers or break lines while the machineis under pressure or while it is running.USE CARE when working near or in line with a compressed spring. Sudden releaseof the spring can cause it and objects in its path to act as projectiles.DO NOT syphon refrigerants or other chemicals by mouth. Check the manufacturersinstructions for correct syphoning procedures.

!

CAUTIONDOUBLE CHECK that coupling nut wrenches, dial indicators, or other items havebeen removed before rotating any shaft. Remember to wear safety glasses.PERIODICALLY INSPECT couplings for proper lubrication and alignment tominimize the possibility of failure and resultant flying particles.TIGHTEN all coupling bolts twice to be sure that none have been overlooked.CHECK coupling locknuts for tightness and for insertion of setscrews.DO NOT weld or flamecut any vessel or line until all refrigerant has been removed.DO NOT loosen a packing gland nut before making sure that it has a positive threadengagement.PERIODICALLY INSPECT all valves, fittings, and piping for corrosion, rust,leaks, or damage.VALVE OFF AND TAG steam, water, and refrigerant lines before opening them.DO NOT step on refrigerant lines. Broken lines can whip about and cause severepersonal injury.USE only repair or replacement parts that meet the code requirements of the originalequipment.

!

SAFETY 2

t Figure 2-38.Oxyacetylene Welding and Cutting Precautions

DANGERDO NOT use oxygen as a substitute for compressed air, or for any purpose otherthan welding or flamecutting.

!

WARNINGDO NOT store oxygen cylinders near combustible material, especially oil andgrease, nor handle oxygen cylinders or apparatus with oily hands or gloves.Oxygen supports and accelerates combustion and will cause oil, grease, and plasticmaterials to burn with great intensity.DO NOT weld or flamecut near combustible materials, nor in an atmospherecontaining refrigerant, nor until pressure vessels and piping have been completelyevacuated.DO NOT weld or flamecut in a confined area unless the area is adequately ventilated.Where it is impossible to provide adequate ventilation, wear SCBA and haveanother person on standby immediately outside the confined area.DO NOT carry a plastic liquid-fuel cigarette lighter or other flammable materialswhile welding, soldering, or brazing. Welding sparks, molten metal, and heat froma torch can ignite the contents of the lighter and cause it to explode.

!

CAUTIONDO NOT store oxygen and fuel gas cylinders near any heat source nor adjacentto each other.STORE oxygen and fuel gas cylinders in an upright position and strap securelyin place.WEAR flame-retardant protective clothing and equipment when welding andflamecutting, and when in the vicinity of such operations.DO NOT block passageways, ladders, and stairways with welding equipment.Use effective safeguards when working on platf