Haier 1U71S2SG1FA Service Manual page 252

Trouble 8: Outdoor unit alarms sensor failure
Start
As per the wiring
diagram, check if
No
connection port
between sensor and
PCB is correct
Yes
Check if the sensor
is in open circuit or
No
the connection port
to PCB is in good
condition
Yes
Replace sensor
and check
again
Trouble 9: AC current over current protection or current transducer damaged, or compressor blocked
rotor, compressor great vibration, compressor abnormal startup, state detecting curcuit abnormal or
compressor damaged.
The former twice failure can be resumed automatically, if outdoor board occurs this failure always, and
can not be resumed for a long time, that shows:
1. Power module (SPDU) damaged, please replace the power module, then re-wiring as per the wiring
diagram (70% possibility)
2. Short circuit in power board results in the power module damaged (15％ possibility)
3. Damaged compressor results in this failure (10％ possibility)
4. Main control board is faulty, replace it (5％ possibility)
Trouble 10: High pressure failure
Reasons:
1. Over high system pressure results that the unit stop, and the compressor protection will work. The
failure can be resumed.
2. Pressure switch wire is not fixed well or in open circuit.
Start
Check if the connector
between pressure
switch and PCB is
fixed badly or damaged
Yes
Replace pressure switch
connector, shut off and
be electrified again,
re-check
Re-fix the
sensor and
check again
Check if the
Replace sensor
No
sensor resistor
and check
value is correct
again
Yes
PCB is faulty
and repalce it,
check again
Check if the 2 straight
No lugs on the pressure
switch are in good
condition
Yes
Replace pressure
switch connector, shut
off and be electrified
again, re-check
If outdoor fan
motor cannot
No No
startup normally
in cooling mode
Yes
Check if the
No
outdoor motor
has power input
249
Replace main
control board
and check again
Replace outdoor
motor and check
again