Download MSG-12CRN1

TROUBLESHOOTING
Diagnostic Chart
(for 12k Models)
If, after energizing the unit, no indicator is lit and the unit cannot be operated, see the following chart.
Be sure all the wires (including power wires and connection wires)
No
are OK
Yes
Install good ones
Check for AC (208-230V) power supply outputs to
outdoor control board
Yes
Check if AC (208-230V) exists at primary coil
No
of transformer (18K & 24K models only)
Outdoor
control board
is Defective
Yes
Check if AC 12V and AC 35V (+5%) exist at secondary coil
of transformer in the outdoor control board
No
Take off the secondary plug of transformer, and then check if AC
Yes
12V and AC 35V (+5%) exist at secondary coil of transformer
Yes
Outdoor
control board
is Defective
No
Transformer is defective
Check if DC 35V exists between
2 & 3 on the indoor terminal
and DC 12V between 3 & 4
No
Yes
Check if DC 35V exists
at CN6 and 12V
at CN3
No
Indoor
control board
is Defective
Yes
Uncertain problem on
Indoor control board.
Change it & check again.
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