Mitsubishi Electric PCA-A24KA7, Service Manual

24

Check code

Abnormal point and detection method 

Cause

Countermeasure

E3

or

E5

Remote controller transmission 
error(E3)/signal receiving error(E5)

1

 Abnormal if remote controller could not 

find blank of transmission path for 6 sec-

onds and could not transmit.

    (Check code: E3)  

2

 Remote controller receives transmitted 

data at the same time and compares the 

received and transmitted data. Abnormal 

if these data are judged to be different 

30 continuous times. (Check code: E3) 

1

 Abnormal if indoor controller board could 

not find blank of transmission path.

   (Check code: E5)   

2

 Indoor controller board receives transmitted 

data at the same time and compares the 

received and transmitted data. Abnormal 

if these data are judged to be different 30 

continuous times. (Check code: E5)

1

 2 remote controllers are set as 

“main.”

    (In case of 2 remote con-
     trollers)

2

 Remote controller is connected 

with 2 indoor units or more.

3

 Repetition of refrigerant address

4

 Defective transmitting receiving 

circuit of remote controller

5

 Defective transmitting receiving 

circuit of indoor controller board

6

 Noise has entered into transmis-

sion wire of remote controller.

1

 Set a remote controller to main, and the 

other to sub.

2

 Remote controller is connected with only 

one indoor unit.

3

 The address changes to a separate setting.

4

–

6 

Diagnose remote controller.

a) When “RC OK” is displayed, remote 

controllers have no problem.

   Turn the power off,and on again to 

check.

   When becoming abnormal again, 

replace indoor controller board.

b) When “RC NG” is displayed, replace 

remote controller.

c) When “RC E3” or “ERC 00-66” is dis-

played, noise may be causing abnor-

mality.

E6

Indoor/outdoor unit communication 

error (Signal receiving error)

1

 Abnormal if indoor controller board 

  cannot receive any signal normally for 6 

minutes after turning the power on.

2

 Abnormal if indoor controller board 

  cannot receive any signal normally for 3 

minutes. 

3

 Consider the unit abnormal under the fol-

lowing condition: When 2 or more indoor 

units are connected to an 

  outdoor unit, indoor controller board 

  cannot receive a signal for 3 minutes 

from outdoor controller circuit board, a 

signal which allows outdoor controller 

circuit board to transmit signals. 

1

 Contact failure, short circuit or, 

miswiring (converse wiring) of 
indoor/outdoor unit connecting 
wire

2

 Defective transmitting receiving 

circuit of indoor controller board

3

 Defective transmitting receiving 

circuit of indoor controller board

4

 Noise has entered into indoor/ 

outdoor unit connecting wire.

   Check LED display on the outdoor control 

circuit board. (Connect A-control service 

tool, PAC-SK52ST.)

  Refer to outdoor unit service manual.

1 

Check disconnection or looseness of 

indoor/ outdoor unit connecting wire of 

indoor unit or outdoor unit.

    Check all the units in case of twin triple   

    indoor unit system.

2

–

4

 Turn the power off, and on again to 

check. If abnormality generates again, 

replace indoor controller board or out-

door controller circuit board.

Note: Other indoor controller board may 

have defect in the case of twin triple 

indoor unit system.

E7

Indoor/outdoor unit communication 
error (Transmitting error)

Abnormal if “1” receiving is detected 30 
times continuously though indoor controller 
board has transmitted “0”.

1

 Defective transmitting receiving 

circuit of indoor controller board 

2

 Noise has entered into power 

supply.

3

 Noise has entered into outdoor 

control wire.

1

–

3

 Turn the power off, and on again to 

check. If abnormality generates again, 
replace indoor controller board.

FB 

(Fb)

Indoor controller board

Abnormal if data cannot be read normally 
from the nonvolatile memory of the indoor 
controller board.

1

 Defective indoor controller board

1

 Replace indoor controller board.

E1

or

E2

Remote controller control board

1

 Abnormal if data cannot be read nor-

mally from the nonvolatile memory of the 

remote controller control board.

    (Check code: E1)

2

 Abnormal if the clock function of remote 

controller cannot be operated normally.

    (Check code: E2)

1

 Defective remote controller

1

 Replace remote controller.

PL

 Abnormal refrigerant circuit

  During Cooling, Dry, or Auto Cooling 

operation, the following conditions are 
regarded as failures when detected for 1 
second.

a) The compressor continues to run for 30 

or more seconds.

b) The liquid pipe temperature or the 

condenser/evaporator temperature is 
167°F [75°C] or more.

These detected errors will not be 
cancelled until the power source is 
reset.

 Abnormal operation of 4-way 

valve

 Disconnection of or leakage in 

refrigerant pipes

 Air into refrigerant piping
 Abnormal operation (no rotation) 

of indoor fan

Â

  Defective fan motor

Â

  Defective indoor control board 

 Defective refrigerant circuit 

(clogging)

 When this error occurs, be sure to 

replace the 4-way valve.

 Check refrigerant pipes for disconnection 

or leakage.

 After the recovery of refrigerant, vacuum 

dry the whole refrigerant circuit.

Refer to 

9-6-2. DC fan motor (fan motor/ 

indoor controller circuit board

.

 Check refrigerant circuit for operation.

 To avoid entry of moisture or air 

into refrigerant circuit which could 
cause abnormal high pressure, purge 
air in refrigerant circuit or replace 
refrigerant.

OCH638