Mitsubishi Mr.SLIM PUH18EK Technical & Service Manual page 22

2. 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 function
(PUH42EK7)
LD6
Thermal switch (26C) function
(PUH42EK7)
(PUH42EK7 )
1
LD7
Over heat protection
LD8
Input circuit of outdoor con-
troller board is abnormal.
3. 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.
This model does not have this
function.
This model does not have this
function.
Outdoor coil thermistor is
broken.
Thermistor was connected
incorrectly.
63H2 was badly connected.
63H2 was working.
51C is working.
26C was connected incorrectly.
26C is working.
The thermistor is broken.
Coil temperature is over
153˚F.
Pulse input is abnormal.
Cause
Cause
No need to be checked.
No need to be checked.
Measure the resistance of the thermistor.
Check the thermistor. If normal, replace the out-
door controller board.
Check 63H2 and the outdoor fan motor.
Check if refrigerant supply is low.
Check if air cycle is short-cycled.
Check 51C.
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 connector and transformers.
4) Check the fuse.
22
Check point
Check points