GE ASYW09CRAWA, Service Manual

Page: 11 / 80

OUTDOOR UNIT CONTROL S and COMPONENTS
PAGE 11
ENGLISH
Discharge Temperature Sensor
Defrost Temperature Sensor
Ambient Temperature Sensor
Suction Line Temperature Sensor
The Discharge Sensor is a negative coefficient thermistor
that senses the temperature of the compressor hot gas.
The PCB will make inverter speed changes in response
to input from this device.
This sensor connects to the PCB at CN20 (09k and 12k),
or CN17 (18k and 24k). .
The Defrost Temperature Sensor is a negative coefficient
thermistor that will change resistance in response to outdoor
coil temperature changes. The Main Control Board monitors
the temperature of the outdoor coil to determine when a
defrost cycle is necessary.The sensor alsomonitors outdoor
coil temperature during defrost cycles todetermine termination
conditions.
This sensor connects to the Main Control Board at PLUG CN-
20.
The Ambient Sensor is a negative coefficient thermistor that
will change resistance in response to temperature changes.
The PCB monitors the temperature of the outdoor air to
determine outdoor fan speed requirements and compressor
speed. The sensor also plays a role in calculation of required
defrost conditions.
This sensor connects to the PCB at CN20 (09k and 12k),
or CN19 (18k and 24k). .
The Suction Line Temperature Sensor is a negative
coefficient thermistor that senses.the temperature
of the suction line to determine EEV orifice size,
maintaining in an attempt to maintain proper operating
superheat.
This sensor connects to the PCB at CN18 (09k and 12k),
or CN47 (18k and 24k).