12037 N Highway 99
Seminole, OK 74868
Phone (405) 382-0731
www.enviro-ok.com
www.safran‐
passenger
‐solutions.com
Copyright © 2020
Original Release
ATA 21‐00‐60
Page | 19
INDICATION
PROBABLE CAUSE
POSSIBLE SOLUTION
F. Compressor Assembly Will
Not Operate
1. Circuit Breaker failed or off
1. Energize or replace
2. System Over Charged/Over
Pressurized
2. Evacuate and Recharge to
correct amount.
3. Pressure switch failed
3. Replace
4. Drive motor failed
4. Replace Compressor Drive
5. Ground power cart not plugged
In
5. Connect as required
6. Low ambient temperature
6. Normal cutout
7. Low refrigerant charge
7. Charge system
8. Controller over temperature
switch open
8. Allow unit to cool. If switch still
open, replace Compressor Drive
G. 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
H. Evaporator Module Coil
Freezing
1. No air flow
1. Turn fan on
2. Expansion valve failed or
clogged
2. Remove debris or replace
I. 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
