62-10848
6-4
6.2.6
Abnormal Pressure - Cooling
High discharge pressure
Condenser coil dirty
Non-condensibles in system
Refrigerant overcharge
Condenser fan/motor defective
Low discharge pressure
Compressor defective
Hot gas solenoid malfunction
Low refrigerant charge
High suction pressure
Compressor defective
Hot gas solenoid malfunction
Compressor pressure regulator mis-adjusted (CPR)
Low suction pressure
Filter–drier partially plugged
Low refrigerant charge
Expansion valve malfunction
No evaporator air flow or restricted air flow
Excessive frost on coil
Check
Suction and discharge pressures
tend to equalize when unit is
operating
Compressor defective
Hot gas solenoid malfunction
6.2.7
Abnormal Pressure - Heating
High discharge pressure
Overcharged system
Condenser fan or HP2 pressure switch defective
Non-condensibles in system
Condenser motor/fan defective
Low discharge pressure
Compressor defective
Hot gas solenoid valve malfunction
Low suction pressure
Low refrigerant charge
Compressor pressure regulating valve mis-adjusted
(CPR)
Condenser Pressure Regulating valve fault (HGS2)
6.2.8
Abnormal Noise
Compressor
Loose mounting bolts
Tighten
Worn bearings
Worn or broken valves
Liquid slugging
Insufficient oil
Check
Condenser or evaporator fan
Loose shroud
Check
Bearings defective
Check
Fan loose on shaft
Check
Bent shaft
Table 6–2 Mechanical Indications (Continued)
Indication/Trouble
Possible Causes
Reference
Section