TM 5-4520-253-13
Table 4-1. Intermediate Maintenance Troubleshooting – Continued
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
1. COMBUSTION
Step 1.
Step 2.
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 two capacitors at end
cover of combustion blower housing before preparing for
any test, check, or when disassembling a component. Dis-
connect fuel solenoid before connecting power cable and
turning heater on for tests or checks. Always have another
person standing by who is trained in electric shock first aid.
BLOWER FAILS TO OPERATE.
Check for loss of power to combustion blower and housing assembly, Be sure
all electrical connections are secure, Connect volt ohmmeter to expose ends of
capacitors at end of housing.
Plug power cable into POWER RECEPTACLE and
move HEATER-OFF-FAN switch quickly from OFF to HEATER to OFF while
observing meter.
Meter should indicate at least 110 V ac.
If no power indicated, proceed to step 2.
Disconnect yellow and white wires (1 and 2) from combustion blower (3) at
quick disconnect terminals (4 and 5). Check voltage across yellow and white
wires back to PC board for 110 V ac. Place probes of volt ohmmeter in ter-
minals (4 and 5) of PC board wires.
Plug power cable into POWER RECEP-
TACLE and move HEATER-OFF-FAN switch quickly from OFF to HEATER
OFF while observing meter.
Meter should indicate at
least 110 V ac.
to
4-3
