Indoor/Outdoor Unit Communication; Indoor Controller Board - Mitsubishi Electric Mr.Slim PKA Series Service Manual

Abnormal point and detection method
Check code
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
E3
30 continuous times. (Check code: E3)
or
E5
1 Abnormal if indoor controller board could
not find blank of transmission path.
(Check code: E5)
2 Indoor controller board receives trans-
mitted data at the same time and com-
pares the received and transmitted data.
Abnormal if these data are judged to be
different 30 continuous times. (Check
code: E5)

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-
E6
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.
Indoor/outdoor unit communication
error (Transmitting error)
Abnormal if "1" receiving is detected 30
E7
times continuously though indoor controller
board has transmitted "0".

Indoor controller board

Abnormal if data cannot be read normally
Fb
from the nonvolatile memory of the indoor
(FB)*
controller board.
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)
E1
or
E2
OCH758
Cause
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 Contact failure, short circuit or,
miswiring (reverse 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.
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 Defective indoor controller
board
1 Defective remote controller
20
Countermeasure
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 "OK" is displayed, remote control-
lers have no problem.
Turn the power off,and on again to check.
When becoming abnormal again, replace
indoor controller board.
b) When "NG" is displayed, replace remote
controller.
c) When "E3" or "ERC" is displayed, noise
may be causing abnormality.
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 occurs again,
replace indoor controller board or outdoor
controller circuit board.
Note:
Other indoor controller board may have defect
in the case of twin triple indoor unit system.
1–3 Turn the power off, and on again to
check. If abnormality occurs again,
replace indoor controller board.
1 Replace indoor controller board.
* The check code in the parenthesis indicates
PAR-40MAA model.
1 Replace remote controller.