TM 5-4520-256-14
3-9. TROUBLESHOOTING - Continued.
Table 3-2. Unit Troubleshooting - Continued
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
10.
HEATER CONTAINS IMPROPER FUEL FOR THE AMBIENT TEMPERATURE - Continued.
Step 16.
Set OFF/VENT/HEAT switch (SI) to the HEAT mode for 20 seconds and catch the fuel from the fuel
line. Proceed to step 17.
Step 17.
Set OFF/VENT/HEAT switch (S1) to OFF. Proceed to step 18.
Step 18.
Refuel the heater with proper fuel. The heater should be functional.
Step 19.
If it is not possible to warm the heater by any means, the fuel lines, filter, and solenoid valves, and
fuel pump will have to be removed and cleaned. Refer to the individual maintenance paragraphs in
Section 3.
11.
BURNER DOES NOT GO OFF WHEN HEATER IS SWITCHED TO VENT MODE. FUEL PRESSURE
REMAINS HIGH.
Step 1.
Set OFF/VENT/HEAT switch (S1) to OFF and quickly back to VENT. Fuel pressure should fall.
If burner remains on, proceed to step 2.
If burner goes off, allow heater to cool; shut down the heater and replace solenoid valve L1 (para 3-34).
Step 2.
If the heater is operating from the internal tank, remove the cap from the external port and switch the
EXTERNAL/INTERNAL valve to EXTERNAL and allow the heater to go off due to loss of fuel.
If the heater is operating from an external tank remove-the fuel line and allow the heater to go off due to
loss of fuel.
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