3-4
62-10630
Table 3-2 Mechanical Indications -- Continued
INDICATION/TROUBLE
POSSIBLE CAUSES
REFERENCE
SECTION
3.2.6 Abnormal Pressure
3.2.6.1 Cooling
High discharge pressure
Condenser coil dirty
Noncondensibles or refrigerant overcharge
Condenser fan/motor defective
4.4
4.10.1
4.13
Low discharge pressure
Compressor defective
Hot gas solenoid malfunction
Low refrigerant charge
4.11
4.14
4.10.1
High suction pressure
Compressor defective
Hot gas solenoid malfunction
Compressor pressure regulator misadjusted (CPR)
4.11
4.14
4.15
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
4.5
4.10.1
3.2.10
3.2.9
Check
Suction and discharge pressures
tend to equalize when unit is
operating
Compressor defective
Hot gas solenoid malfunction
4.11
4.14
3.2.6.2 Heating
High discharge pressure
Overcharged system
Condenser fan or HP2 pressure switch defective
Noncondensibles in system
Condenser motor/fan defective
4.10.1
4.12
4.7.1
4.13
Low discharge pressure
Compressor defective
Hot gas valve malfunction
4.11
4.14
Low suction pressure
Low refrigerant charge
Compressor pressure regulating valve misadjusted (CPR)
Condenser Pressure Regulating valve fault (HGS2)
4.10.1
4.15
4.14
3.2.7 Abnormal Noise
Compressor
Loose mounting bolts
Worn bearings
Worn or broken valves
Liquid slugging
Insufficient oil
Tighten
4.11
4.11
3.2.10
Check
Condenser or evaporator fan
Loose shroud
Bearings defective
Fan loose on shaft
Bent shaft
Check
Check
Check
3.2.8 Cab Command Malfunction
Cab Command non–operational
Fuse open
Microprocessor malfunction
Microprocessor/Cab command cable
Replace
Replace
Check
3.2.9 No Evaporator Air Flow or Restricted Air Flow
Evaporator coil blocked
Heavy frost on coil
Coil dirty
Check
4.3
No or partial evaporator air flow
Evaporator fan loose or defective
Evaporator fan rotating backwards
Evaporator air flow blocked in box
Fan motor(s) malfunction
Check
Check
Check
Replace