Temperature Sensors - Haier 2U18MS2VHB Service Manual

Temperature Sensors

The outdoor unit has two groups of temperature sensors. The first group of sensors are Liquid and Gas Sensors that are
associated with each indoor unit EEV. These sensors monitor the leaving liquid temperature from the EEV and the returning
Suction Vapor temperature from the indoor units. The difference between the two temperatures is used to calculate the
operational suction vapor superheat level of each calling indoor unit. These sensors are labeled Tc1 and Tc2 on the schematic
drawing. They plug into the ECU unit on a series of plugs located near the center of the circuit board.
The second group of sensors monitor key temperatures in the refrigeration circuit and outdoor unit. The sensors associated
with the refrigeration circuit include compressor discharge line temperature, compressor suction line temperature, outdoor
coil entering gas temperature, outdoor coil temperature cooling mode and outdoor coil heat mode temperature (Defrost).
The ambient outdoor air temperature is monitored by sensor Ta. The temperature of the heat sink attached to the Module
Board is monitored by Sensor Tm. These sensors connect to the ECU via plugs CN-7 and CN-14.
Compressor Compressor
Discharge Line Discharge Line
Temperature Temperature
Sensor Sensor
Components
Outdoor Coil Cooling Outdoor Coil Cooling
Temperature Sensor Temperature Sensor
Outdoor coil Outdoor coil
Heat Mode Heat Mode
Temperature Temperature
Sensor Sensor
(Defrost) (Defrost)
OUTDOOR TECHNICAL OVERVIEW
Outdoor Coil Outdoor Coil
Entering Gas Entering Gas
Temperature Temperature
Sensor Sensor
Module Module
Heat Sink Heat Sink
Temperature Temperature
Sensor Sensor
Compressor Compressor
Suction Line Suction Line
Temperature Temperature
Sensor Sensor
B-7