TM 9-4120-403-14
TABLE 4-2. UNIT TROUBLESHOOTING (cont)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
4. COMPRESSOR STARTS NORMALLY, BUT HIGH OR LOW PRESSURE CUT-OUT SWITCH SOON TRIPS.
Step 1. Check that fan blades are tight and are operating freely.
If not operating properly; see paras 4-55b, evaporator fan and 4-56b, condenser fan.
Step 2. With unit operating in COOL mode, check condition of refrigerant in sight glass.
If indicator color is in the yellow zone or numerous bubbles appear in the window, turn selector
switch to OFF and notify your supervisor.
Step 3. Reset (PUSH) PRESSURE CUT-OUT switch(es) and restart unit.
If unit does not start notify your supervisor.
5. REDUCED COOLING CAPACITY
Step 1. Check operation of fan toggle switch (S7).
Switch from LO to HI SPEED. If no change results, test switch. (See para 4-29.) Replace
defective switch.
4-18