TM 9-4520-260-13
4-24. OVERHEAT SWITCH AND FLAME SWITCH
This task covers:
a. Inspection
b. Testing
c. Removal
d. Installation
INITIAL SETUP
Tools
Equipment Condition
Tool Kit, Service Refrigeration Unit
Power disconnected.
Material/Parts
Tags
General Safety Instructions
The ignition system of this heater contains
dangerous voltages which can cause severe electri-
cal shock. Be sure to disconnect power before any
maintenance actions.
NOTE
Both the overheat switch and the flame switch may be visually inspected as described
below. Both switches may be confidence tested at ambient temperatures as described in
TESTING, below. Complete electrical testing, sufficient to ensure proper operation of
the switches, requires a heat source and temperature measuring equipment not available
to Unit Maintenance personnel. If the proper operation of the heater from which the
switches were removed cannot be verified, then both switches must be discarded upon
removal and new switches installed in INSTALLATION.
Visually check overheat switch (2) and flame switch (6) for the following conditions. Replace a switch that has any of the
following problems:
a. Damaged terminals.
c. Cracks.
d. Evidence of overheating or arcing.
4-47