Mitsubishi Electric PUHZ-SHW80VHA Service Manual page 73

Indication
Outdoor controller board
LED1 (Green) LED2 (Red)
3 blinking 1 blinking
Abnormality of discharging
temperature (TH4) and Comp.
surface temperature (TH34)
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)
4 blinking Compressor overcurrent
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, TH34)
Open/ short of outdoor thermistors
(TH3, TH32, TH33, TH6, TH7
and TH8)
Abnormality of heatsink
6 blinking
temperature
7 blinking
Abnormality of voltage
4 blinking 1 blinking Abnormality of room temperature thermistor (TH1)
Abnormality of pipe temperature thermistor / Liq uid (TH2)
Abnormality of pipe temperature
thermistor/ Condenser-Evaporator
Abnormality of drain sensor (DS)
2 blinking
Float switch connector open (FS)
Indoor drain overflow protection
3 blinking
Freezing (cooling)/ overheating
(heating) protection
4 blinking Abnormality of pipe
temperature
* Check code displayed on remote controller
* * Refer to service manual for indoor unit.
OCH526C
Check
Contents
code*
1Check if stop valves are open.
U2
2Check if connectors (TH4, LEV -A, and LEV -B ) on outdoor controller
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 ex p ansion 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 ex c h anger and filter is not dirty.
4Measure resistance values among terminals on linear ex p ansion 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
U6
1Check if connectors(TH3, TH32, TH33, TH4, TH34 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).
U9
1Check looseness, disconnection, and converse connection of
compressor wiring.
2Measure resistance value among terminals on compressor using a tester.
3Check if power supply voltage decreases.
4Check the wiring of CN52C.
5Check the wiring of CNAF.
1Check if connectors (CN20, CN21, CN29 and CN44) on indoor
P1
controller board are not disconnected.
P2
2Measure resistance value of indoor thermistors.
P9
P4 1Check if connector (CN31)(CN4F) on indoor controller board is not
disconnected.
2Measure resistance value of indoor thermistors.
3Measure resistance value among terminals on drain pump using
P5
a tester.
4Check if drain pump works.
5Check drain function.
P6
1Check if indoor unit has a short cycle on its air duct.
2Check if heat ex c h anger and filter is not dirty.
3Measure resistance value on indoor and outdoor fan motors.
4Check if the inside of refrigerant piping is not clogged.
1Check if indoor thermistors(TH2 and TH5) are not disconnected from holder.
P8
2Check if stop valve is open.
3Check converse connection of ex tension pipe. (on plural units connection)
4Check if indoor/ outdoor connecting wire is connected correctly.
(on plural units connection)
Error
Inspection method
Detailed
reference
page
P.35
P.36
P.35
P.38
P.36
P.38
P.38
P.39
P.38
P.36
P.35
P.36
P.36
P.37
* *
* *
* *
* *
P.41
P.41