TM 9-2350-261-34
20. Turn the heater control switch to OFF. Fuel
flow and burning should stop in about 30
seconds. Blower should continue to run from
1 to 3 minutes and then stop. If blower
does not work within limits, readjust the
flame detector switch (see your -20). If the
blower still fails to work within limits,
replace the flame detector switch
(see your –20).
TESTING RESTRICTION
THERMOSTAT AND
THERMOSTATIC SWITCH
21. Turn the heater on and run it until the
coolant is hot enough to make the heater
cycle from high to low heat. Leave the
heater alone, then take the temperature of
the coolant. The temperature should be
between 140°F (60°C) and 170°F (76°C). If
coolant temperature is not within limits,
replace restriction thermostat (page 14–51).
22. After testing the restriction thermostat,
close circuit across terminal board terminals
No. 4 and No. 5, to make the heater stay
on high heat. Heat the coolant until the
heater burning stops. Check the temperature
of the coolant, it should be not less than
220°F (104°C) or more than 250°F ( 21°C).
If the coolant temperature is not within
these limits, replace the thermostatic switch
(page 14–53).
N O T E
Thermostat shown in fuel control valve is
set to open at 70°F (21°C) and to close at
30°F (-1°C). If temperature is below 70°F
(21°C), the heating element in fuel control
valve can be energized during any
operational cycle.
FOLLOW-THROUGH STEPS
1. Install coolant heater in carrier
(see your -20).
END OF TASK
14-66
