TM 5-4520-256-14
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Step 3.
Place the ends of the ducts close together to force warm air into the return air duct. Proceed to step
4.
Step 4.
Connect the proper fuel supply to the external fuel port and place the EXTERNAL/INTERNAL fuel
valve to the EXTERNAL fuel position. Proceed to step 5.
Step 5.
Set OFF/VENT/HEAT switch (S1) to VENT mode and purge the system (para 1-14b) as well as
possible. Proceed to step 6.
Step 6.
Attempt to start the heater allowing warm air to enter the heater through the ductwork. Do not allow
the inlet side of the heater to get above 100°F. Proceed to step 7.
Step 7.
Repeat steps 5 and 6 until the heater pump, filter, and fuel lines have been purged of the improper
fuel and the heater operates properly. Proceed to step 8.
Step 8.
Raise the heater and drain the internal fuel tank. Proceed to step 9.
Step 9.
Refill the heater with the proper fuel and proceed to step 10.
Step 10.
If the heater will not fire at all, obtain another heater or heat source to blow warm air into the non
functioning heater and perform steps 4 through 9 after the heater is warmed.
If another heater is unavailable, proceed to step 11.
Step 11.
Move the heater to a warm location/building and allow the heater to thaw.
If it is not possible to move the heater proceed to step 19.
If the heater can be moved, proceed to step 12.
Step 12.
After the heater thaws, lift the heater and drain the fuel cell. Proceed to step 13.
Step 13.
Connect the proper fuel supply to the heater external fuel port and place the EXTERNAL/INTERNAL
fuel valve to the EXTERNAL position. Proceed to step 14.
Step 14.
Disconnect the fuel line to the nozzle and place the end into a container to catch fuel. Proceed to
step 15.
Step 15.
Supply 115 Vac to the heater and set the OFF/VENT/HEAT switch (S1) to the VENT mode and
purge the fuel lines (para 1-14b) for at least two minutes. Proceed to step 16.
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