TM 5-4520-256-14
3-9. TROUBLESHOOTING- Continued.
Table 3-2. Unit Troubleshooting - Continued
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
9.
THERMOSTATS DO NOT CONTROL THE BURNER OR SHELTER TEMPERATURE - Continued.
Step 7.
Set OFF/VENT/HEAT switch (S1) to HEAT mode.
If the ambient temperature is above 50°F, set the thermostats as low as possible to cycle the burner off.
If the burner cycles with the thermostats, the heater is functional.
If the burner does not cycle, replace the temperature controller (para 3-28).
If the ambient is too low to cycle the burner, proceed to step 8.
WARNING
While performing step 8, be careful when placing jumpers on contacts. Contacts 1 and 2 contain
115 Vac and can cause personnel injury or loss of life.
Step 8.
Set OFF/VENT/HEAT switch (S1) to HEAT and place a small jumper wire between contacts 5 and 6
of the temperature controller to cause a short circuit. The burner should cycle off.
If the burner cycles off, the heater is functional.
If the burner does not cycle off, replace the temperature controller (para 3-28).
10.
HEATER CONTAINS IMPROPER FUEL FOR THE AMBIENT TEMPERATURE.
Step 1.
Attempt to start the heater.
If the heater will fire, even for only a few seconds, proceed to step 2.
If the heater will not fire at all, proceed to step 10.
Step 2.
Disconnect the return and supply air ducts from the shelter. Proceed to step 3.
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