Section 22: HEATING AND AIR CONDITIONING
PA1553
21
4. Check compressor oil level to ensure
compressor is not overcharged with oil.
Sometimes a significant amount of oil is
pumped out of the compressor to other
parts of the system when a compressor
fails. This oil will return to the replacement
compressor when it is started, causing an
overcharge of oil in the sump of the
replacement compressor. In this case, it is
important that the oil level be adjusted to
the proper level.
5. Withdraw a sample of the compressor oil and
check its color, odor, and acidity, using
instructions supplied above. If the oil is
contaminated, change the oil and filter dryer,
and repeat the procedure until the system is
clean.
8.7.3 Clean-out After Major Compressor
Failure
1. Reclaim the refrigerant into a refrigerant
bottle through a filter dryer to filter out
contaminants.
2. Remove the failed compressor and repair it if
possible.
3. Install new or repaired compressor.
4. Change the filter dryer.
5. Circulate clean R-134a or nitrogen with the
reclaimer to clean out many of the
contaminants collected in the coil valves,
TXV (Thermal Expansion Valve), solenoid
valves, check valves, and any other
mechanical component that may have
collected contaminants.
6. Evacuate and charge the system normally.
7. Run the unit for 8 hours and monitor the
pressure drop across the filter dryer. Also
check the liquid line dryer for signs of
restriction. If the pressure drop across the
filter dryer exceeds 12 to 14 psig (82,75 to
96,5 kPa) with a 40°F (5°C) evaporator coil
temperature, stop the unit and change the
liquid line and suction line filter dryer. After 4
or 5 hours of operation, stop the unit and
replace the filter dryer.
8. After 8 hours of operation, stop the unit and
remove a sample of the compressor oil and
check its color, odor, and acidity, using
instructions supplied above. If the oil is
contaminated, replace the oil and repeat step
7. If the oil is not contaminated, change the
filter dryer again and replace the moisture-
liquid indicator.
9. After approximately 7 days of operation,
recheck the compressor oil for cleanliness
and acidity.
9. CENTRAL HVAC SYSTEM – AIR
CONDITIONING COMPONENTS
9.1 COMPRESSOR (CENTRAL SYSTEM)
9.1.1 Belt Replacement
DANGER
Turn the ignition key switch to the “Off”
position. For greater safety, trip circuit
breakers CB1 & CB2 and set the engine
starter selector switch in engine compartment
to the “Off” position.
1. Open engine compartment rear doors and
locate the belt tensioner pressure releasing
valve (Fig. 18), mounted above the engine
R.H. side door next to the air pressure
regulator, then turn handle clockwise in
order to release pressure and tension on
belts.
2. Slip the old belts off and the new ones on.
3. Reset belt tensioner pressure releasing
valve (Fig. 18) to 45 psi (310 kPa) to apply
tension on the new belts as explained in
Section 12.
FIGURE 18: AIR PRESSURE REGULATOR 12200
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