Mitsubishi Electric PCA-A24GA Service Manual page 18

Abnormal point and detection method
Error 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.
E6
3 Consider the unit as abnormal under the
following condition: When 2 or more
indoor units are connected to 1
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 normally read
Fb
from the nonvolatile memory of the indoor
controller board.
Remote controller control board
1 Abnormal if data cannot be normally
read from the nonvolatile memory of the
remote controller control board.
E1
(Error code: E1)
or
E2
2 Abnormal if the clock function of remote
controller cannot be normally operated.
(Error code: E2)
Forced compressor stop
(due to water leakage abnormality)
1 When the intake temperature subtracted
with liquid pipe temperature is less than
-10:(14˚F), drain sensor detects
whether it is soaked in the water or not
at the interval of 90 seconds. (Drain
pump will start operating when the drain sen-
sor detects to be soaked in the water.)
2 The unit has a water leakage abnormality
when the following conditions, a and b,
are satisfied while the above-mentioned
detection is performed.
a) The drain sensor detects to be
soaked in the water 10 times in a row.
PA
b) The intake temperature subtracted
(2502)
with liquid pipe temperature is detect-
(2500)
ed to be less than -10:(14˚F) for a
total of 30 minutes. (When the drain
sensor detects to be NOT soaked in
the water, the detection record of a
and b will be cleared.)
3 The drain sensor detection is performed
in operations other than cooling. (When
the unit stops operating, during heating
or fan operation, when the unit stops
because of some abnormality)
*Once the water leakage abnormality is
detected, abnormality state will not be
released until the main power is reset.
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.
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 drain sensor
side heater
4 Contact failure of drain sensor
connector
5 Dew condensation on drain
sensor
· Drain water trickles along
lead wire.
· Drain water waving due to filter
clogging
6 Extension piping connection
difference at twin system
7 Miswiring of indoor/ outdoor
connecting at twin system
8 Room temperature thermistor /
liquid pipe temperature thermis-
tor detection is defective.
18
Countermeasure
Check LED display on the outdoor control cir-
cuit board. (Connect A-control service tool,
PAC-SK52ST.)
Refer to EA-EC item if LED displays EA-EC.
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 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.
Other indoor controller board may have
defect in case of twin 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 Please confirm whether water can be
drained.
3 Confirm the resistance of the drain sensor.
4 Check the connector contact failure.
5 Check the drain sensor 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
display of outdoor controller board.