Mitsubishi PUMY-P60NKMU Technical & Service Manual page 37

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 controller board.
Is the voltage normal?
Is it free from any trace of over-
heating or burning?
Continue to the next page
OCH502C
Low pressure trouble
Diagnosis
Yes
(dirty)
(no dirt)
No
Yes
(short-cycled)
(no short-cycle)
No
Yes
(dirty)
(no dirt)
No
Yes
No
No
No
Yes
No
Yes
No
Yes
Wash the indoor heat exchanger.
Wash the outdoor heat exchanger.
Replace the indoor LEV
Replace the indoor controller board.
37
Chart 2 of 3
Remedy
Solve the short-cycle.
Defective pipes.
Replace the TH7.