Component Maintenance Manual
EFFECTIVITY: ALL
21-00-22
Page
1007
JULY 21, 2011
INDICATION PROBABLE
CAUSE POSSIBLE
SOLUTION
G. Compressor Assembly Will
Not Operate
1. Circuit Breaker failed or off
1. Energize or replace
2. Relay failed
2. Replace
3. Pressure switch failed
3. Replace
4. Drive motor failed
5. Replace
5. Drive motor fuse blown
6. Replace
6. Ground power cart not plugged
in
7. Connect as required
7. Low ambient temperature
8. Normal cutout
8. Low refrigerant charge
9. Charge system
9. Motor temperature switch failed
10. Replace switch
H. No Evaporator Module Air
Flow
1. Circuit breaker off
1. Energize or replace
2. Mode switch failed
2. Replace
3. Fan speed switch failed
3. Replace
4. Seized motor
4. Replace
5. Blower wheel failed
5. Replace
6. Blocked air ducts
6. Remove debris
7. Aircraft power not on
7. Energize
8. Ground power not on
8. Energize
I. Evaporator Module Coil
Freezing
1. No air flow
1. Turn fan on
2. Expansion valve failed or
clogged
2. Remove debris or replace
3. Expansion valve setting low
3. Reset to obtain 26-30 psig
suction pressure
J Pressure Switch Cycles (High
Pressure Cutout)
1. System over charged
1. Reclaim refrigerant as required
2. Condenser coil inlet air
extremely hot
2. Normal condition
3. Condenser inlet clogged
3. Remove debris
4. Discharge line clogged or
kinked
4. Replace or straighten line
5. Excessively high ambient
temperature
5. Normal Condition
Table 3 Trouble Shooting List
