Mitsubishi Electric PLA-RP35EA Service Manual page 23

Abnormal point and detection method
Check code
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
E6
following 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
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.
E1
(Check code: E1)
or
E2
2 Abnormal if the clock function of remote
controller cannot be operated normally.
(Check code: E2)
Forced compressor stop
(due to water leakage abnormality)
1 The unit has a water leakage abnor-
mality when the following conditions, a)
and b), are satisfied while the above-
mentioned detection is performed.
a) The intake temperature subtracted
with liquid pipe temperature detects
to be less than −10: for a total of
30 minutes. (When the drain sensor
is detected to be NOT soaked in the
water, the detection record of a) and b)
will be cleared.)
b) Drain float switch detects to be in the
water for more than 15 minutes.
PA
Note: Once the water leakage abnormality
is detected, abnormality state will not
be released until the main power is
reset.
OCH626A
Cause
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.
5 Malfunction of fan motor
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
1 Drain pump trouble
2 Drain defective
• Drain pump clogging
• Drain pipe clogging
3 Open circuit of float switch
4 Contact failure of float switch
connector
5 Dew condensation on float
switch
• Drain water descends along
lead wire.
• Drain water is waving due to
filter clogging.
6 Extension piping connection
difference at twin, triple or
quadruple system
7 Miswiring of indoor/ outdoor
connecting at twin, triple or
quadruple system
8 Room temperature thermistor/
liquid pipe temperature thermis-
tor detection is defective.
23
Countermeasure
Note: 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 outdoor
controller circuit board.
5 Turn the power off, and on again after remov-
ing the fan motor connectors (CNF1,2) from
outdoor controller board.
• If normal, change fan motor.
• If abnormal reappears, change outdoor
controller 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 generates again, replace
indoor controller board.
1 Replace indoor controller board.
1 Replace remote controller.
1 Check the drain pump.
2 Check whether water can be drained.
3 Check the resistance of the float switch.
4 Check the connector contact failure.
5 Check the float switch leadwire mounted.
Check the filter clogging.
6 Check the piping connection.
7 Check the indoor/outdoor connecting wires.
8 Check the room temperature display of
remote controller.
Check the indoor liquid pipe temperature dis
play of outdoor controller board.