TM 5-4520-208-15
Probable cause
Possible remedy
57. Electric Motor Power Unit Fails to Stop
Power unit operating
Tighten belt or adjust
Probable cause
Possible remedy
below normal speed.
engine rpm.
ON-OFF switch defective -- Replace ON-OFF switch
60. Combustor Fire Cuts Out on Overheat
58. Heater Ignition Fails
Possible remedy
Probable cause
Air inlet door closed
Open air inlet door or
Note. To determine whether the above trouble is
or obstructed.
remove obstruction.
caused by a faulty ignition system of fuel system, fol-
Restriction in discharge
Straighten bent ducts.
low the method below to expedite locating the fault:
air stream.
Replace a collapsed duct.
Remove the fan mounting ring and remove the nozzle
Replace valve (para 100).
Temperature selector
clamp and combustor plate (para 77). If raw fuel is
valve heat sensing
present in the combustion chamber, inspect trouble
element capillary tube
symptoms pertaining to ignition system. If no raw
ruptured.
fuel is present in the combustion chamber, inspect the
Fuel control valve sensing
Inspect for proper
trouble symptoms pertaining to the fuel system.
positioning (para 100).
element improperly
Probable cause
Possible remedy
positioned in air
V-belt slipping or broken__ Adjust V-belt (para 47)
stream.
or replace V-belt.
Igniter plug defective ---_ Adjust or replace igniter
61. Combustor Fire Fails to Cut Out on
plug (para 83).
Overheat
Magneto points improperly Adjust magneto points
set or defective.
Possible remedy
Probable cause
Magneto points burned or Replace burned or pitted
Replace fuel control valve
Fuel control valve
pitted.
points (para 82).
temperature sensing
Heater fuel filter clogged _ - Replace fuel filter
element capillary tube
(BT400-40). Service
ruptured.
fuel filter (BT400-40-1).
Ignition cable defective ----- Inspection ignition cable
62. Discharge Air Temperature not in
for damage. Replace
Correct Range
damaged ignition cable
Possible remedy
Probable cause
Temperature selector
Set valve to correct
Magneto pulley slipping. ___ Check fit of pulley or
temperature.
valve improperly set.
replace pulley (para 82).
Check temperature with an
Temperature gage
Fuel supply low (electric Fill fuel tank (para 10).
defective.
accurate thermometer.
motor power unit
Replace defective
installed).
temperature gage
Tube assemblies clogged
Clean, thaw, or replace
or frozen.
tube assemblies (para 84,
BT400-40 or para 90,
63. Discharge Air Temperature Fluctuates
BT400-40-1).
Tighten all connections.
Fuel control valve
Possible remedy
Probable cause
connection loose.
Replace temperature
Temperature selector
valve defective.
selector valve (para
Fuel pump pulley
Tighten setscrew or replace
slipping.
pulley (para 82).
100) .
Clean the fuel nozzle or
Replace defective
Fuel nozzle dirty or
Defective temperature
defective.
replace the nozzle (para
temperature gage (para
gage.
99) .
92, BT400-40-1).
Fuel pump defective_______ Replace fuel pump (para
64. Maximum Heat Output Not Obtainable
Possible remedy
Probable cause
90, BT400-40-1).
Fuel system leaks _________ Tighten all fuel connec-
59. Heater Exhaust Smoking Excessively
ions. Replace damaged
tube assemblies (para 85,
Possible remedy
Probable cause
BT400-40 or para 90,
Air inlet door closed __ -____ Open air inlet door.
BT400-40-1).
Air inlet screen
Clean air inlet screen.
Replace temperature
Temperature selector
clogged.
selector valve (para 100).
valve defective.
Nozzle spray pattern
Remove mounting ring,
Fuel pump defective-------Replace fuel pump (para
incorrect.
nozzle clamp, and
combustor plate (para
90(BT400-40-1).
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