FINAL TEST COOLANT HEATER Continued
TESTING RESTRICTION AND OVERHEAT THERMOSTATS
Turn heater on and run it until coolant is hot enough to make heater cycle from high to low heat. Leave heater alone, then
take temperature of coolant. The temperature should be between 140
C) and 170
C). If coolant temperature
is not within limits, replace restriction thermostat (WP 0067 00).
Thermostat shown in fuel control valve is set to open at 70
C) and to close at 30
If temperature is below 70
C), the heating element in fuel control valve can be energized
during any operational cycle.
After testing restriction thermostat, close circuit across terminal board terminals No. 4 and No. 5, to make heater stay on
high heat. Heat coolant until heater burning stops. Check temperature of coolant which should be not less than 220
C) or not more than 250
C). If coolant temperature is not within these limits, replace overheat thermostat
(WP 0068 00).
Install coolant heater in carrier (see your -20).
END OF TASK