ARMY TM 9-4120-380-14
AIR FORCE TO 35E9-136-21
CRANKCASE HEATER (HR3).This task covers inspection, testing, adjustment, removal and installation.
Tool kit, service, refrigeration unit (Item 1, Appendix B)
Disconnect input power to the air conditioner before performing any internal
maintenance Voltages used can KILL. Shutting the unit off at the control panel does not
disconnect unit power.
Disconnect air conditioner input power at source;
Verify CB2 is closed (paragraph 4 39).
a. Check crankcase heater wires in J-box for corrosion or loose electrical connections.
b. Check for signs of overheating or other visible damage. Replace heater if defective.
The following test must be conducted with power on. Use extreme caution and follow
steps carefully. Death or senous injury may result.
a. Connect air conditioner power at source.
c. If no current flow is indicated, disconnect air conditioner power at source and replace crankcase heater.