Mitsubishi Electric PUMY-P112VKM1 Service Manual page 51

Check code
1300
●Diagnosis of defectives
Make sure to turn the power OFF before connecting/disconnecting any connectors, or replacing boards.
Continued from the previous page
Is there dirt on the indoor heat
exchanger?
Is the outdoor unit short-cycled?
Is there dirt on the outdoor heat
exchanger?
Are pipes clogged or broken?
Disconnect the outdoor temperature
thermistor wiring and check the resistance.
Is there a resistance detected?
Disconnect the indoor LEV wiring to check
the resistance.
Is there a resistance detected?
Check the voltage and appearance of the
outdoor multi controller circuit board.
Is the voltage normal?
Is it free from any trace of over-
heating or burning?
Continue to the next page
OCH576
Low pressure trouble
Diagnosis
(dirty)
No (no dirt)
(short-cycled)
(no short-cycle)
No
(dirty)
(no dirt)
No
No
No
Yes
Yes
Yes
Yes Wash the indoor heat exchanger.
Yes
Yes
Wash the outdoor heat exchanger.
Yes
No
No
No
Replace the indoor controller board.
51
Chart 2 of 3
Remedy
Solve the short-cycle.
Defective pipes
Replace the TH7.
Replace the indoor LEV.