TM9-4120-400-14
TROUBLESHOOTING - continued
Table 4-2.
MALFUNCTION
TEST OR INSPECTION
C O R R E C T I V E ACTION
5. COMPRESSOR WILL NOT START. - continued
Step 8. Observe operation of time delay relay. (See para 4-29.)
Replace bad relay.
Step 9. Substitute compressor relay known to be good, and check operation. (See para 4-31.)
Replace bad relay.
NOTE
Compressor start capacitor (single phase unit using keco compressor only) is not
connected to start relay.
Step 10. Test compressor start capacitor (single phase unit using welco compressor only) .
(See para 4-37.)
Replace bad capacitor.
Step 11. Test compressor motor by checking continuity of the following pins at the compressor electrical
receptacle. (See fig. 4-4 for pin identifications.)
(1) Pins A and B, B and C, and C and A. Continuity should exist.
(2) Pins A, B, and C and compressor housing. No continuity should exist.
(3) Pins D and E. Continuity should exist when compressor is cool enough for internal
thermostat to be closed. If compressor is hot, let cool and retest.
Report faulty motor to supervisor.
COMPRESSOR SHORT CYCLES.
Step 1. Check for obstructions in front of condenser screen.
Remove obstructions and/or roll up and secure canvas cover.
Step 2. Check for dirt in condenser coil. (See para 4-48.)
Clean condenser coil.
Step 3. Check if HIGH PRESSURE cutout switch RESET is tripped.
Push and release HIGH PRESSURE switch to RESET.
Step 4. Check if LOW PRESSURE cutout switch RESET is tripped.
Push and release LOW PRESSURE switch to RESET.
4-34
