Mitsubishi Electric PUZ-WM50VHA Service Manual page 51

Indication
Outdoor controller board
LED1 (Green) LED2 (Red)
3 blinking 1 blinking
Abnormality of discharging
temperature (TH4) and Comp.
surface temperature (TH33)
Abnormality of superheat due
to low discharge temperature
Abnormal high pressure (High
2 blinking
pressure switch 63H operated.)
Abnormal low pressure (Low
pressure switch 63L operated.)
3 blinking Abnormality of outdoor fan
motor rotational speed
Protection from overheat
operation (TH3)
Compressor overcurrent
4 blinking
breaking(Start-up locked)
Compressor overcurrent breaking
Abnormality of current sensor (P.B.)
Abnormality of power module
Open/short of outdoor
5 blinking
thermistors (TH4, TH33)
Open/short of outdoor thermistors
(TH3, TH32, TH6, TH7 and TH8)
Abnormality of heat sink
6 blinking
temperature
7 blinking Abnormality of voltage
4 blinking 1 blinking Abnormality of room temperature
thermistor (TH1)
Abnormality of pipe temperature
thermistor /Liquid (TH2)
Abnormality of tank temperature
thermistor
4 blinking
Abnormality of pipe
temperature
* Check code displayed on remote controller
** Refer to service manual for indoor unit.
OCH727
Check
Contents
code*
1Check if stop valves are open.
2Check if connectors (TH4, LEV-A, and LEV-B) on outdoor controller
U2
board are not disconnected.
3Check if unit is filled with specified amount of refrigerant.
4Measure resistance values among terminals on indoor valve and
outdoor linear expansion valve using a tester.
U7
1Check if indoor/outdoor units have a short cycle on their air ducts.
U1
2Check if connector(63H)(63L) on outdoor controller board is not disconnected.
3Check if heat exchanger and filter is not dirty.
4Measure resistance values among terminals on linear expansion valve
UL
using a tester.
1Check the outdoor fan motor.
U8
2Check if connector (TH3) (63HS) on outdoor controller board is disconnected.
Ud
1Check if stop valves are open.
UF
2Check looseness, disconnection, and converse connection of
compressor wiring.
3Measure resistance values among terminals on compressor using a tester.
UP
4Check if outdoor unit has a short cycle on its air duct.
UH
5Check leakage of refrigerant.
U6
1Check if connectors (TH3, TH32, TH4, TH33 and TH7/6) on outdoor
U3
controller board and connector (CN3) on outdoor power board are not
disconnected.
2Measure resistance value of outdoor thermistors.
U4
1Check if indoor/outdoor units have a short cycle on their air ducts.
U5
2Measure resistance value of outdoor thermistor(TH8).
1Check looseness, disconnection, and converse connection of
compressor wiring.
2Measure resistance value among terminals on compressor using a tester.
U9
3Check if power supply voltage decreases.
4Check the wiring of CN52C.
5Check the wiring of CNAF.
1Check if connectors on indoor controller board are not disconnected.
P1
2Measure resistance value of indoor thermistors.
P2
P9
1Check if indoor thermistors(TH2 and TH5) are not disconnected from holder.
2Check if stop valve is open.
3Check converse connection of extension pipe. (on plural units connection)
P8
4Check if indoor/outdoor connecting wire is connected correctly.
(on plural units connection)
Error
Inspection method
51
Detailed
reference
page
P.25
P.26
P.25
P.29
P.26
P.28
P.28
P.29
P.28
P.26
P.25
P.26
P.26
P.27–
P.28
**
**
**
P.31