Mitsubishi Electric PUZ-HWM140VHA, Service Manual

Page: 46 / 74

46
OCH748
Indication Error
Detailed
reference
page
Outdoor controller board
Contents
Check
code*
Inspection method
LED1 (Green) LED2 (Red)
3 blinking 1 blinking Abnormality of discharging
temperature (TH4) and Comp.
surface temperature (TH33)
U2
1
Check if stop valves are open.
2
Check if connectors (TH4, LEV-A, and LEV-B) on outdoor con-
troller board are not disconnected.
3
Check if unit is filled with specified amount of refrigerant.
4
Measure resistance values among terminals on indoor valve and
outdoor linear expansion valve using a multimeter.
P.22
Abnormality of superheat due to
low discharge temperature
U7 P.23
2 blinking Abnormal high pressure (High
pressure switch 63H operated.)
U1
1
Check if indoor/outdoor units have a short cycle on their air ducts.
2
Check if connector (63H) (63L) on outdoor controller board is not
disconnected.
3
Check if heat exchanger and filter is not dirty.
4
Measure resistance values among terminals on linear expansion
valve using a multimeter.
P.22
3 blinking
Abnormality of outdoor fan motor
rotational speed
U8
1
Check the outdoor fan motor.
2
Check if connector (TH3) (63HS) on outdoor controller board is
disconnected.
P.23
Protection from overheat
operation (TH3)
Ud P.25
4 blinking Compressor overcurrent
breaking(Startup locked)
UF
1
Check if connecting wire of indoor unit or remote controller is
connected correctly.
2
Check if noise entered into transmission wire of remote controller.
3
Re-check error by turning off power, and on again.
P.25
Compressor overcurrent breaking UP P.25
Abnormality of current sensor (P.B.)
UH P.25
Abnormality of power module U6 P.23
5 blinking Open/short of outdoor
thermistors (TH4, TH33)
U3
1
Check if connectors (TH3, TH32, TH4, TH33 and TH7/6) on
outdoor controller board and connector (CN6) on outdoor power
board are not disconnected.
2
Measure resistance value of outdoor thermistors.
P.22
Open/short of outdoor thermistors
(TH3, TH32, TH6, TH7 and TH8)
U4 P.23
6 blinking Abnormality of heat sink
temperature
U5
1
Check if indoor/outdoor units have a short cycle on their air ducts.
2
Measure resistance value of outdoor thermistor (TH8).
P.23
7 blinking
Abnormality of voltage
U9
1
Check looseness, disconnection, and converse connection of
compressor wiring.
2
Measure resistance value among terminals on compressor using
a multimeter.
3
Check if power supply voltage decreases.
P.24
4 blinking 1 blinking Abnormality of room temperature
thermistor (TH1)
P1
1
Check if connectors on indoor controller board are not discon-
nected.
2
Measure resistance value of indoor thermistors.
**
Abnormality of pipe temperature
thermistor /Liquid (TH2)
P2 **
Abnormality of tank temperature
thermistor
P9 **
4 blinking Abnormality of pipe
temperature
P8
1
Check if indoor thermistors(TH2 and TH5) are not disconnected
from holder.
2
Check if stop valve is open.
3
Check converse connection of extension pipe. (on plural units
connection)
4
Check if indoor/outdoor connecting wire is connected correctly.
(on plural units connection)
P.27
* Check code displayed on remote controller
** Refer to service manual for indoor unit.