Haier 1U18BR4EAA Service Manual page 16

8.3 Problem Symptoms and Measures
Symptom Check Item
Check the power supply.
None of the units
operates
Check the indoor PCB
Operation
Check the power supply.
sometimes stops.
Check for faulty operation
of the electronic
Equipment
operates but
expansion valve.
does not cool, or
does not heat
(only for heat
pump)
Diagnosis by service port
pressure and operating
current.
Large operating
noise and Check the installation
vibrations condition.
Details of Measure
Check to make sure that the rated voltage is supplied.
Check to make sure that the indoor PCB is broken
A power failure of 2 to 10 cycles can stop air conditioner
operation.
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.
Check for insufficient gas.
Check to make sure that the required spaces for
installation (specified in the Technical Guide, etc.) are
provided.
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Service diagnosis
Domestic air conditioner