Operating instructions

TM 11574A-OI
3-51
Step Probable Cause Remedy
5 Expansion valve setting too high. Lower setting.
If fault is not corrected proceed to step 6.
6 Iced or dirty evaporators. Defrost or clean evaporators.
e. Unit operates long or continuously.
Step Probable Cause Remedy
1 Low refrigerant charge. Add refrigerant.
If fault is not corrected proceed to step 2.
2 Control contacts fused. Replace controls.
If fault is not corrected proceed to step 3.
3 Air in system. Recover.
If fault is not corrected proceed to step 4.
4 Partially plugged or plugged expansion valve
or strainer.
Clean or replace expansion valve or
strainer.
If fault is not corrected proceed to step 5.
5 Defective insulation. Replace or repair insulation.
If fault is not corrected proceed to step 6.
6 Service load. Keep doors and windows closed.
If fault is not corrected proceed to step 7.
7 Inefficient compressor. Check valves.
If fault is not corrected proceed to step 8.
8 Condenser scaled. Clean condenser.
If fault is not corrected proceed to step 9.
9 Restricted evaporator air. Defrost coil, clean filters and ductwork.