Low Pressure Trouble - Mitsubishi PUMY-P60NKMU Technical & Service Manual

Check code
1300
Abnormal points and detection methods
<63L equipped model (63LS non-equipped)>
(1) Low pressure (63L is in operation)
Abnormal if 63L operates (under-0.03MPa) during compressor
operation.
<63LS equipped model (63L non-equipped)>
(2) Low pressure (63LS is in operation)
Abnormal if 63LS operates (under-0.03MPa) during compressor
operation.
63L : Low pressure switch
63LS : Low pressure sensor
LEV : Linear expansion valve
SV1 : Solenoid valve
TH7 : Outdoor temperature thermistor
●Diagnosis of defectives
Make sure to turn the power OFF before connecting/disconnecting any connectors, or replacing boards.
Is the outdoor stop valve (ball
valve) fully open ?
Does the the outdoor fan rotare
while the operation?
Does the indoor fan rotate while
the operation?
Is the indoor unit short-cycled?
Is the indoor unit fi lter clogged?
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OCH502C

Low pressure trouble

Diagnosis
No
Yes
No
Yes
No
Yes
Yes
(short-cycled)
(no short-cycle)
No
Yes
(fi lter clogged)
(no clog)
No
Causes and check points
Defective operation of stop valve (not fully open)
Clogged or broken pipe.
Malfunction or locked outdoor fan motor
Short-cycle of outdoor unit
Dirt of outdoor heat exchanger
Remote controller transmitting error caused by noise interference
Contact failure of outdoor controller board connector
Defective outdoor controller board
Short-cycle of indoor unit
Decreased airfl ow, clogged fi lter, or dirt on indoor unit.
Malfunction or locked indoor fan motor.
Decreased airfl ow caused by defective inspection
of outdoor temperature thermistor (It detects lower
temperature than actual temperature.)
Indoor LEV performance failure
Malfunction of fan driving circuit
SV1 performance failure
Defective low-pressure sensor
Malfunction of low-pressure sensor input circuit on
outdoor conrtoller board
Open the stop valve (ball balve) fully.
Check the outdoor fan motor
Refer to "How to check the parts" on
outdoor unit servive manual.
Check the indoor fan motor
Refer to "How to check the parts" on
indoor unit servive manual.
36
Chart 1 of 3
Remedy
Solve the short-cycle.
Clean the fi lter.