TM 9-4520-260-13
Table 4-1. Unit Preventive Maintenance Checks and Services - Continued
Item To Be
Item
Interval
Checked or
Procedure
Not Fully Mission
No.
Serviced
capable If:
8
Quarterly
Air Duct Hose
Check for cracks or holes. Replace a defective hose
Hose or clamp is
damaged.
9
Quarterly
Room
Check for loose terminals or restricted movement of
Room thermostat
Thermostat
is defective.
10
Annually
Motor Brushes
Remove brushes and inspect for cracks, broken rings,
Brushes are
distorted springs, and wear. Replace if defective
defective.
SECTION III. UNIT TROUBLESHOOTING
4-8. INTRODUCTION TO TROUBLESHOOTING.
This troubleshooting procedure allows Unit Maintenance personnel to isolate and remedy equipment faults and return the
WARNING
The heater ignition system contains dangerous voltages which can cause severe
electrical shock.
Be extremely careful when troubleshooting while heater is
connected to power source. Always disconnect power when making continuity
checks.
MALFUNCTION INDEX
Page No.
HEATER
Fails to start - no flame, no blower ........................................................................................
Fails to start - blower runs for a short time then stops ...........................................................
Smokes or backfires .........................................................................................................
Cycles ON-OFF excessively
..........................................................................................
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