TM 5-4520-241-14
Table 5-1. Direct Support and General Support Troubleshooting - Continued
MALFUNCTION
TESTING OR INSPECTION
CORRECTIVE ACTION
1 - Continued
Replace the burner head if it is damaged, or if it cannot be cleaned by wirebrushing to remove
combustion deposits. No repairs are authorized. Clean heat exchanger while burner head is
removed. Install a new burner head in the reverse order of removal.
Step 4.
Check for power to the combustion air motor. Turn off the heater power. Remove the louvered
panel adjacent to the combustion motor. This should provide sufficient access to the combustion
motor terminals to permit a voltage check. Connect an AC voltmeter to the exposed ends of the
suppression capacitors on top of the combustion motor assembly. Momentarily move the
HEATER-OFF-FAN switch to HEATER. 120 volts AC should be present. Tighten loose
connections or replace broken lead if no power is present.
Step 5.
Check wiring inside combustion motor assembly. Disconnect the power plug, open the access
doors, and remove the louvered panels. Disconnect the combustion motor leads at the terminal
strip. Remove screw (1, fig. 5-1) and lock washers (2) through support tube (3), and remove
support tube. Remove nuts (4) and washers (5, 6, and 7) securing motor assembly to heater case.
Disconnect air duct from motor housing (19). Pull out motor assembly. Remove screws (8) and
lock washers (9). Separate top motor housing assembly (10) from bottom motor housing assembly
(13).
Pull out assembled motor housing (19) and combustion motor (32). Remove sealing tape and pry
off housing from motor. If necessary, remove nut (14), screw (15), and lock washer (16) to remove
ground strap (17). Test continuity through suppression capacitors (23) using test light or ohmmeter.
Replace capacitors if they are open. Unsolder wires at capacitor terminals. Remove nuts (21)
and washers (22) securing capacitor (23) to motor housing (19). Install new capacitors and
resolder wires using rosin core electrical solder. Continue testing per steps 6 and 7 before
5-4
