Mitsubishi Electric PCH-2GKHA Service Manual page 54

4. TROUBLESHOOTING ACCORDING TO CHECK CODE
Blinking
Diagnosis of malfunction
LED
LD1 Reversed phase
LD2
Open phase
LD3 Outdoor coil thermistor is
abnormal. (Open circuit or short
circuit)
LD4 High pressure switch (63H2)
function
LD5 Thermal relay (51C) function
LD6 Thermal switch (26C) function.
LD7 Over heat protection
LD8 Input circuit of outdoor
controller board is abnormal.
5. WHEN OUTDOOR UNIT DOES NOT WORK
1) Indoor/outdoor connecting wires are poorly connected.
(Refer to next page.)
2) Power supply is poorly connected.
3) Connector or transformer is broken.
4) Fuse (6A) in the outdoor controller board is blown.
54
Phases L , L
1
connected improperly.
Phase L
2
Contact of protector, such as
thermal switch, opened when
power was turned on.
Outdoor coil thermistor is
broken.
Thermistor was connected
incorrectly.
62H2 was badly connected.
63H2 was working.
51C was connected
incorrectly.
51C was working.
26C was connected
incorrectly.
26C is working.
The thermistor is broken.
Coil temperature is over
67°C.
Pulse input is abnormal.
Cause
Cause
, and L are Check the power supply connection.
2 3
is open. Check the power supply.
Check each protector.
Measure the resistance of the thermistor.
Check the thermistor. If normal, replace the
outdoor controller board.
Check 63H2 and the outdoor fan motor.
Check if refrigerant supply is low.
Check if air cycle is short-cycled.
Check 51C, the compressor, and power supply.
Check 26C.
Check if refrigerant supply is low.
Check if the capillary tube is clogged.
Measure the resistance of the thermistor.
Check the outdoor fan motor.
Check if air cycle is short-cycled.
Replace the outdoor controller board.
1) Check the connecting wires.
2) Check the power supply.
3) Check connectors and transformers.
4) Check the fuse.
Check point
Check points