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