TM 5-4520-253-13
l N S P E C T / T E S T / R E M O V E / l N S T A L L S A F E T Y T H E R M O S T A T S A N D F L A ME
S W I T C H A N D B R A C K E T A S S E M B LY
TOOL EQUIPMENT: Volt ohmmeter
Thermometer [range up to 300° F (
TOOLS: Tool kit, service, refrigeration unit
NSN 5180-00-596-1474
49°C)]
MATERlALS/PARTS: Wire, insulated, heat resistant
GENERAL SAFETY INSTRUCTIONS:
Power off.
Heater cool.
INSPECTION:
Death or serious injury could occur if precautions are not
taken when maintaining this equipment. Position HEATER-
OFF-FAN switch to OFF, remove power cable plug from
POWER RECEPTACLE, and ground capacitors C1 and C2
prior to gaining access to heater compartments. Terminals
of capacitors are accessible at end cover of combustion
blower. Always disconnect power cable before making con-
tinuity tests or before repairing heater. Always have
another person standing by who is trained in electric shock
first aid.
Allow sufficient time for heater to cool to room tempera-
ture before gaining access to heater compartments.
1. Open access door (1) by unlocking one stud (2). Locate thermostat mounting bracket (3) and
flame switch and bracket assembly (4).
2. Remove two screws (5) and lock washers (6) at mounting bracket (3) and lift out bracket and
overheat thermostat (7). The thermostat is covered by shield (8).
3. Check thermostat (7) for cracks, dents, or other signs of damage or overheating.
4. Check for bent or missing shield (8).
5. Check terminal connections of wires (9) for good electrical contact.
6. Replace defective thermostat (7).
7. Remove two screws (10) and lock washers (11) and lift out flame switch and bracket assembly (4).
Assembly (4) carries overheat thermostat (12) which is identical to thermostat (7).
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