AIR CONDITIONING SYSTEM TESTS, INSPECTIONS, AND ADJUSTMENTS - CONTINUED
GENERAL - CONTINUED
All charging and leak testing must be done in a well ventilated area.
Avoid any physical contact with refrigerant.
Place a clean cloth over any valve or any connection that is opened.
Never weld any charged components.
Never solder any charged components.
Never steam clean any charged components.
Dispose of any oil that is polyalkaline glycol (PAG) that has been opened but not used. Moisture will contaminate
unused oil and air conditioning system.
These procedures may give direction to replace wiring harnesses. However, limited repair of wiring harnesses is autho-
rized. Refer to Electrical General Maintenance Instructions (WP 0022 00) for the correct repair procedures.
In order to check function of compressor, disconnect hose from inlet of inline dryer. Measure pressure of suction of
compressor. Pressure should be a vacuum between 24 to 28 inHg (81 to 95 kPa). Do not operate compressor for more
than 2 minutes when system pressure is below vacuum.
Secure lines and wires in order to prevent damage to lines and wires.
Formation of black sludge deposits in system is caused by presence of moisture in R-134a systems and by mixing
charges of R-134a and R-12. Black sludge deposits can cause a blockage in system.
Presence of white foam during recovery is normal. Foam is caused by mixing of oil and refrigerant.
R-134a system charges must be within 1.000 to 2.000 oz (0.03 to 0.06 kg) of specified charge for machine.
A drain line that is plugged or a drain line that is pinched may cause a backup of condensation and leakage into cab.
Missing drain valves may cause a backup of condensation and leakage into cab.
Missing drain valves will allow dust to be sucked into evaporator coil and heater coil.
A cab pressure of 0.200 to 0.600 in. of H2O (0.05 to 0.15 kPa) and proper maintenance of air conditioner filter will
result in the following conditions:
Reduction of dust.
Reduction of noise.
More efficient HVAC performance.
A loss of cooling ability of system and failure of compressor may be caused by one or more of following conditions:
Too much oil.
Too little oil.
Dirty filter or plugged filter.
Dirty evaporator or plugged evaporator.
Dirty orifice tube or plugged orifice tube.
Dirty expansion valve or plugged expansion valve.
Too much moisture in system.