Haier GE 2U18MS2HDA Service Manual page 29

[10] Outdoor defrosting temperature sensor Te abnormal
[11] Suction temperature sensor Ts abnormal
[12] Outdoor ambient temperature sensor Ta abnormal
[13] Discharging temperature sensor Td abnormal
Sensor temperature has been detected below or higher than expected,
or has been detected as a shorted or open circuit
(for expected temperature, refer to part failure code)
Possible causes:
• Bad sensor connection
• The sensor is bad
• Sensor resistance drift
• The temperature acquired by PCB is not accurate
[15] Communication abnormal between indoor unit and outdoor unit
Outdoor unit control board cannot communicate
with the indoor unit control board for over 4
minutes.
Possible causes:
• Bad communication wiring
• The PCB is bad
Troubleshooting
Power off
Is the communication wire
shorted?
Is the communication wire
CN21 disconnected?
Is the wiring connection sequence
correct according to the wiring
diagram?
Power on
Measure the outdoor terminal block voltage
between communication 3 and N, and measure the
indoor terminal block between communication 3
and N to check. Is the communication wire ok?
Using a multimeter, measure the terminal
corresponding to the N-line voltage
of CN21 from the indoor unit with the
communication failure. Is the voltage
normal?
ERROR CODES & TROUBLESHOOTING
Is the sensor wiring
firmly and correctly in
place?
Yes
Is the sensor
resistance within
range?
Yes
Is the temperature
loop acquired by
the computer board
normal?
Yes
No
Yes
No
No
Yes
No
Yes
No
No
Replace
sensor
No
Replace
sensor
Yes
Replace
it.
Replace wire
econnect
R
econnect
R
Replace the
communication wire
PCB is bad, replace
PCB
PAGE 29