Troubleshooting - Mitsubishi Electric SEZ-KD25VAQ.TH Service Manual

6

TROUBLESHOOTING

6-1. CAUTIONS ON TROUBLESHOOTING
(1) Before troubleshooting, check the followings:
1 Check the power supply voltage.
2 Check the indoor/outdoor connecting wire for mis-wiring.
(2) Take care the followings during servicing.
1 Before servicing the air conditioner, be sure to turn off the remote controller first to stop the main unit, and then turn
off the breaker.
2 When removing the indoor controller board, hold the edge of the board with care NOT to apply stress on the
components.
3 When connecting or disconnecting the connectors, hold the housing of the connector. DO NOT pull the lead wires.
6-2. SELF-CHECK FUNCTION
Wired remote controller
(1) Turn on the power.
(2) Press the [CHECK] button twice.
(3) Set refrigerant address with [TEMP] button
if system control is used.
(4) Press the [ON/OFF] button to stop the
self-check.
A A CHECK button
B B Refrigerant address
C C TEMP button
D D IC : Indoor unit
OC : Outdoor unit
E E Check code
• For description of each check code, refer to the following table.
1 Check code
P1 Intake sensor error
P2 Pipe (TH2) sensor error
P9 Pipe (TH5) sensor error
E6,E7 Indoor/outdoor unit communication error
P4 Drain sensor error
P5 Drain pump error
P6 Freezing/Overheating protection operation
EE Communication error between indoor and outdoor units
P8 Pipe temperature error
E0, E3~E5 Remote controller transmission error
E1, E2 Remote controller control board error
Fb Indoor unit control system error (memory error, etc.)
E9 Indoor/outdoor unit communication error (Transmitting error) (Outdoor unit)
UP Compressor overcurrent interruption
U3,U4 Open/short of outdoor unit thermistors
UF Compressor overcurrent interruption (When compressor locked)
U2 Abnormal high discharging temperature/49C worked/insufficient refrigerant
U1,Ud Abnormal high pressure (63H worked)/Overheating protection operation
U5 Abnormal temperature of heat sink
U8 Outdoor unit fan safeguard stop
U6 Compressor overcurrent interruption/Abnormal of power module
U7 Abnormality of super heat due to low discharge temperature
U9,UH Abnormality such as overvoltage or voltage shortage and abnormal synchronous signal to main circuit
/Current sensor error
Others Other errors (Refer to the technical manual for the outdoor unit.)
• On wired remote controller.
1 Check code displayed in the LCD.
Lead wires
C
PAR-21MAA
Symptom
20
B E D
˚C
˚C
SIMPLE
TEMP. ON/OFF
MENU ON/OFF
FILTER
BACK MONITOR/SET DAY CHECK TEST
CLOCK OPERATION CLEAR
A
Remark
For details, check the LED display
of the outdoor controller board.
As for outdoor unit, refer to
service manual OC322.