TM 9-4120-385-14
(d) Remove terminal box cover. Disconnect thermostats witch lead from
crankcase heater lead. Check continuity between pin G and thermostat switch lead. If
continuity is not indicated, stitch is defective.
NOTE
Crankcase heater thermostat is normally closed and is set to open at 120 F
F.
(49 C) +/- 5 F. Switch should close at 105 F (41 C)
(e) Reconnect P3 to J3 and unit power supply. Operate the unit for 60 minutes
o n maximum COOLER. Disconnect Power at P3. Recheck continuity as above. If
continuity is indicated, switch is defective and should be replaced.
To Test Crankcase Heater
3.
WARNING
High voltage can kill.
CAUTION
All covers should be in plain and secure while unit is operating.
(a) Disconnect power supply.
(b) Disconnect P3 from J3.
(c) Remove the terminal box cover. Using a multimeter set on the ohm scale,
check the continuity at the heater lead and pin F. If continuity is not indicated, heater is
defective and should be replaced. See Figure 5-12.
f. REPAIR.
WARNING
Make sure compressor and heater are cool before touching. Severe
burns can result from touching while hot.
Repair burned out compressor or compressor motor by replacement
of entire unit.
5-42
