Heating and Air Conditioning: Service Precautions

WARNING:
- ON VEHICLES EQUIPPED WITH AIRBAGS, DISABLE THE AIRBAG SYSTEM BEFORE ATTEMPTING ANY STEERING WHEEL, STEERING COLUMN, OR INSTRUMENT PANEL COMPONENT DIAGNOSIS OR SERVICE. DISCONNECT AND ISOLATE THE BATTERY NEGATIVE (GROUND) CABLE, THEN WAIT TWO MINUTES FOR THE AIRBAG SYSTEM CAPACITOR TO DISCHARGE BEFORE PERFORMING FURTHER DIAGNOSIS OR SERVICE. THIS IS THE ONLY SURE WAY TO DISABLE THE AIRBAG SYSTEM. FAILURE TO TAKE THE PROPER PRECAUTIONS COULD RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL INJURY.
- TAKE CARE NOT TO OPEN THE DISCHARGE (HIGH PRESSURE) VALVE AT THIS TIME.
- THE ENGINE COOLING SYSTEM IS DESIGNED TO DEVELOP INTERNAL PRESSURES OF 97 TO 123 KILO PASCALS (14 TO 18 POUNDS PER SQUARE INCH). DO NOT REMOVE OR LOOSEN THE COOLANT PRESSURE CAP, CYLINDER BLOCK DRAIN PLUGS, RADIATOR DRAIN, RADIATOR HOSES, HEATER HOSES, OR HOSE CLAMPS WHILE THE SYSTEM IS HOT AND UNDER PRESSURE. FAILURE TO OBSERVE THIS WARNING CAN RESULT IN SERIOUS BURNS FROM THE HEATED ENGINE COOLANT. ALLOW THE VEHICLE TO COOL FOR A MINIMUM OF 15 MINUTES BEFORE OPENING THE COOLING SYSTEM FOR SERVICE.
- THE ENGINE COOLING-SYSTEM CONTAINS ANTIFREEZE. ANTIFREEZE IS AN ETHYLENE GLYCOL BASED COOLANT AND IS HARMFUL IF SWALLOWED OR IF THE VAPORS ARE INHALED. IF SWALLOWED, DRINK TWO GLASSES OF WATER AND INDUCE VOMITING. IF VAPORS ARE INHALED, MOVE TO AN AREA FOR FRESH AIR. SEEK MEDICAL ATTENTION IMMEDIATELY. DO NOT STORE IN OPEN OR UNMARKED CONTAINERS. WASH SKIN AND CLOTHING THOROUGHLY AFTER COMING IN CONTACT WITH ETHYLENE GLYCOL. KEEP OUT OF REACH OF CHILDREN.
- THE AIR CONDITIONING SYSTEM CONTAINS REFRIGERANT UNDER HIGH PRESSURE. SEVERE PERSONAL INJURY MAY RESULT FROM IMPROPER SERVICE PROCEDURES. REPAIRS SHOULD ONLY BE PERFORMED BY QUALIFIED SERVICE PERSONNEL.
- AVOID BREATHING THE REFRIGERANT AND REFRIGERANT OIL VAPOR OR MIST. EXPOSURE MAY IRRITATE THE EYES, NOSE, AND/OR THROAT. WEAR EYE PROTECTION WHEN SERVICING THE AIR CONDITIONING REFRIGERANT SYSTEM. SERIOUS EYE INJURY CAN RESULT FROM DIRECT CONTACT WITH THE REFRIGERANT. IF EYE CONTACT OCCURS, SEEK MEDICAL ATTENTION IMMEDIATELY.
- WHEN REFRIGERANT IS BURNED. AN ELECTRONIC LEAK DETECTOR IS RECOMMENDED.
- IF ACCIDENTAL SYSTEM DISCHARGE OCCURS, VENTILATE THE WORK AREA BEFORE RESUMING SERVICE. LARGE AMOUNTS OF REFRIGERANT RELEASED IN A CLOSED WORK AREA WILL DISPLACE THE OXYGEN AND CAUSE SUFFOCATION.
- THE EVAPORATION RATE OF R-134a REFRIGERANT AT AVERAGE TEMPERATURE AND ALTITUDE IS EXTREMELY HIGH. AS A RESULT, ANYTHING THAT COMES IN CONTACT WITH THE REFRIGERANT WILL FREEZE. ALWAYS PROTECT THE SKIN OR DELICATE OBJECTS FROM DIRECT CONTACT WITH THE REFRIGERANT.
- THE R-134a SERVICE EQUIPMENT OR THE VEHICLE REFRIGERANT SYSTEM SHOULD NOT BE PRESSURE TESTED OR LEAK TESTED WITH COMPRESSED AIR. SOME MIXTURES OF AIR AND R-134a HAVE BEEN SHOWN TO BE COMBUSTIBLE AT ELEVATED PRESSURES. THESE MIXTURES ARE POTENTIALLY DANGEROUS, AND MAY RESULT IN FIRE OR EXPLOSION CAUSING INJURY OR PROPERTY DAMAGE.

CAUTION:
- Liquid refrigerant is corrosive to metal surfaces. Follow the operating instructions supplied with the service equipment being used.
- Never add R-12 to a refrigerant system designed to use R-134a. Damage to the system will result.
- R-12 refrigerant oil must not be mixed with R-134a refrigerant oil. They are not compatible.
- Do not use R-12 equipment or parts on the R-134a system. Damage to the system will result. All parts, tools, and equipment must be designed for R-134a refrigerant.
- Do not discharge refrigerant into the atmosphere. Use an R-134a refrigerant recovery/re-cycling device that meets SAE Standard J2210.
- The refrigerant must be recovered completely from the system before opening any fitting or connection. Open the fittings with caution, even after the system has been discharged. If any pressure is noticed as a fitting is loosened, tighten the fitting and recover the refrigerant from the system again.
- The refrigerant system must always be evacuated before charging.
- Do not overcharge the refrigerant system. This will cause excessive compressor head pressure and can cause noise and system failure.
- Do not open the refrigerant system or remove the sealing caps from a replacement component until it is to be installed. This will prevent contamination in the system.
- Before disconnecting a component, clean the outside of the fittings thoroughly to prevent contamination from entering the refrigerant system.
- When it is necessary to open the refrigerant system, have everything needed to service the system ready. Immediately after disconnecting a component from the refrigerant system, seal the open fittings with a cap or plug to prevent the entrance of dirt and moisture. The refrigerant system should not be left open to the atmosphere any longer than necessary.
- Before connecting an open refrigerant fitting, always install a new seal or gasket. All fittings with O-rings need to be coated with refrigerant oil before installation. Use only O-rings that are the correct size and approved for use with R-134a refrigerant. Failure to do so may result in a leak. Coat the fitting and seal with clean refrigerant oil before connecting. Unified plumbing connections with gaskets cannot be serviced with O-rings. The gaskets are not reusable and new gaskets do not require lubrication before installing.
- When installing a refrigerant line, avoid sharp bends that may restrict refrigerant flow. A good rule for the flexible hose refrigerant lines is to keep the radius of all bends at least ten times the diameter of the hose. Sharp bends will reduce the flow of refrigerant.
- Position the refrigerant lines away from exhaust system components or any sharp edges, which may damage the line. The flexible hose lines should be routed so they are at least 80 millimeters (3 inches) from the exhaust manifold. Inspect all flexible refrigerant system hose lines at least once a year to make sure they are in good condition and properly routed.
- High pressures are produced in the refrigerant system when it is operating. Extreme care must be exercised to make sure that all refrigerant system connections are pressure tight.
- Tighten refrigerant fittings only to the specified torque. The aluminum fittings used in the refrigerant system will not tolerate overtightening.
- When disconnecting a refrigerant fitting, use a wrench on both halves of the fitting. This will prevent twisting of the refrigerant lines or tubes.
- Refrigerant oil will absorb moisture from the atmosphere if left uncapped. Do not open a container of refrigerant oil until you are ready to use it. Replace the cap on the oil container immediately after using. Store refrigerant oil only in a clean, airtight, and moisture-free container.
- All tools, including the refrigerant recycling equipment, the manifold gauge set, and test hoses should be kept clean and dry. Keep the work area clean. Contamination of the refrigerant system through careless work habits must be avoided. The refrigerant system will remain chemically stable as long as pure, moisture-free R-134a refrigerant and refrigerant oil is used. Dirt, moisture, or air can upset this chemical stability. Operational troubles or serious damage can occur if foreign material is introduced to the refrigerant system.