Haier Unitary smart series Service Manual page 188

13) Troubleshooting (before replacement of PCB)
Service call
Fault confirmation
Confirm operating
conditions
Is the feature not
available for present
product?
no
Switch on air
conditioner
Does the same
fault occur before?
yes
Switch off air conditioner
temporarily.
on air conditioner again
after 1 minute
yes
Does the same
fault occur before?
yes
Disconnect contactor
and reconnect it.
(check if fuse or
varistor is broken.)
no
Does the same
fault occur before?
yes
Check the system thoroughly,
e.g. technical data of
components when power-off,
and voltage and current of
check points when power-on
For example: no cooling, etc.
1.Is supply voltage acceptable?
2.Is temperature setting correct? (e.g. too high)
3.Is system in TIMER mode?
4.Is user aware of product features, etc.
yes
Explain product
features to user
No need to replace mainboard. (Check
operating status in details, e.g. TIMER feature,
no
supply failure, thunder storm, interference from
other appliances, etc.) Explain causes of fault
to user.
no
No need to replace mainboard. The fault may
be caused by power supply
no
No need to replace mainboard. Contactor
wasn't in good contact
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