ARMY TM 10-4610-309-14
MARINE CORPS TM 10802A-14/1
0064 00
TACTICAL WATER PURIFICATION SYSTEM (TWPS)
UNIT MAINTENANCE PROCEDURES
COLD WEATHER SYSTEM
Diesel Heater Motor Relay and Motor Testing/Replacement:
Parts (TM 10-610-309-24P):
Diesel heater motor starting relay
Diesel heater motor and pump assembly
Tool:
Test/ground lead with alligator clips or comparable wire for jumping between two terminals
Equipment condition:
Diesel heater OFF and power cord disconnected from source and from heater
When the diesel heater motor fails to start, check to make sure the power cord is in good condition and
plugged in. Also check that the thermostat is in operating condition and set to call for heat. If the power
cord and thermostat check out, there may be a problem with the motor relay or the motor.
Test the diesel heater motor relay and motor as follows:
WARNING
Electrical hazard. Before working on the motor relay and motor, be sure the heater
power switch is OFF and the power cord is unplugged from the power source and
the heater. Then, when power is required, be extremely careful not to let any part
of your person touch bare wires, leads, or terminals. Failure to observe this
warning may result in serious injury from electrical shock.
1. Remove the motor starting relay as follows:
a. Make sure the heater power switch is OFF.
b. Make sure the heater power cord is unplugged from the power source and from the
heater.
c. Remove the three screws that secure the screen to the inlet duct adapter and remove the
screen.
d. (See Figure 5) Remove the two screws that hold the motor starting relay to its bracket
inside the inlet end of the heater shell and gently pull the relay out as far as the wires will
reach. (If the wires are bound with a plastic tie-wrap, it may be necessary to clip the tie-
wrap.)
2. Test the motor starting relay and motor as follows
a. Tag and remove the black motor wire from terminal three (3) of the starting relay.
b. Clip one end of the jumper to terminal three (3) of the starting relay.
c. Clip the other end of the jumper to terminal two (2) of the starting relay.
d. Make sure the relay is oriented in the same position as when it is installed in the heater.
The relay is position sensitive.
e. Make sure the heater thermostat is set to call for heat.
0064 00-7
