Service Manual
13
ELECTRONIC CONTROL
OPERATION
Heat Pump Models
If the indoor ambient air themister reads 55 degrees or
lower, the control will turn off the compressor and turn
on the electric heat and continue fan operation until temp
setting is satised. Then revert to standard heat pump
operation.
If the compressor is time delayed, the control will:
1. Turn on the electric heat until the compressor is not time
delayed.
2. When the compressor’s 3 minute time delay is over,
turn off the electric heat, wait 5 seconds, then turn on the
compressor.
Defrost:
If the outdoor coil thermister reads 30 degrees or lower
for 2 minutes continuously, the control will turn off the
compressor and turn on the electric heat and continue fan
operation.
Positioning of the Coil Sensors (Thermisters) is critical to
proper operation of the Electronic Control.
Ensure that sensors are positioned as indicated in the
illustrations below.
If the outdoor coil thermister reaches 43 degrees and
the compressor has waited the standard delay time of
180-240 seconds, the control will:
1. Turn off the backup electric heat
2. Wait 5 seconds
3. Turn on the compressor
4. Continue fan operation.
ELECTRIC SHOCK HAZARD
WARNING
Disconnect power to the unit before
servicing. Failure to follow this warning
could result in serious injury or death.
COIL SENSORS
FAN MOTOR - TEST
1. Make sure the motor has cooled down.
2. Disconnect the fan motor wires from the control board.
3. Test for continuity between the windings also, test to
ground.
4. If any winding is open or grounded replace the motor.
Fan Motor
FAN MOTOR
A single phase permanent split capacitor motor is used to drive
the evaporator blower and condenser fan. A self-resetting
overload is located inside the motor to protect against high
temperature and high amperage conditions. (See Figure 23)
ELECTRIC SHOCK HAZARD
WARNING
Disconnect power to the unit before
servicing. Failure to follow this warning
could result in serious injury or death.
COMPONENTS TESTING