Haier AS25THMHRA-C, Service Manual, Page: 501 / 537

Service diagnosis
29
Domestic air conditioner
10. Service Diagnosis
10.1 Caution for Diagnosis
The operation lamp flashes when any of the following errors is detected.
1. When a protection device of the indo
●
or or outdoor unit is activated or when the thermistor malfunctions, disabling
equipment operation.
2. When a signal transmission error occurs between the indoor and outdoor units. In either case, conduct the diagnostic
procedure described in the following pages.
10.2 Problem Symptoms and Measures
Symptom Che
●
ck Item Details of Measure
None of the units
operates
Check the power supply. Check to make sure that the rated voltage is supplied.
Check the indoor PCB Check to make sure that the indoor PCB is broken
Operation
sometimes stops.
Check the power supply.
A power failure of 2 to 10 cycles can stop air conditioner
operation.
Equipment
operates but does
not cool, or does
not heat (only for
heat pump)
Check for faulty operation
of the electronic
expansion valve.
Set the units to cooling operation, and compare the
temperatures of the liquid side connection pipes of the
connection section among rooms to check the opening and
closing operation of the electronic expansion valves of the
individual units.
Diagnosis by service port
●
pressure and operating
current.
●
Check for insufficient gas.
Large operating
●
noise and
vibrations
Check the installation
condition.
Check to make sure that the required spaces for
installation (specified in the Technical Guide, etc.) are
provided.