Mitsubishi Electric PLA-A12EA8 Service Manual page 21

Check code Abnormal point and detection method
Forced compressor stop
(due to water leakage abnormality)
1 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 intake temperature subtracted with
liquid pipe temperature detects to be
less than 14°F [−10°C] for a total of
30 minutes. (When the drain sensor
PA
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.
Note:
Once the water leakage abnormality is
detected, abnormality state will not be
released until the main power is reset.
Remote controller transmission
error(E0)/signal receiving error(E4)
1 Abnormal if main or sub remote con-
troller cannot receive any transmission
normally from indoor unit of refrigerant
address "0" for 3 minutes.
(Check code: E0)
2 Abnormal if sub remote controller could
not receive any signal for 2 minutes.
(Check code: E0)
E0
1 Abnormal if indoor controller board can
or
not receive any data normally from
E4
remote controller board or from other
indoor controller board for 3 minutes.
(Check code: E4)
2 Indoor controller board cannot receive
any signal from remote controller for 2
minutes. (Check code: E4)
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
E3
if these data are judged to be different
or
30 continuous times. (Check code: E3)
E5
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)
TCH120A
Cause
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 trickles down
lead wire.
• Drain water ripples 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.
1 Contact failure at transmission
wire of remote controller
2 All remote controllers are set as
"sub" remote controller. In this
case, E0 is displayed on remote
controller, and E4 is displayed
at LED (LED1, LED2) on the
outdoor controller circuit board.
3 Miswiring of remote controller
4 Defective transmitting receiving
circuit of remote controller
5 Defective transmitting receiving
circuit of indoor controller board
of refrigerant addresses "0".
6 Noise has entered into the
transmission wire of remote
controller.
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.
21
Countermeasure
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 lead wire 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.
1 Check disconnection or looseness of indoor unit or
transmission wire of remote controller.
2 Set one of the remote controllers "main"
if there is no problem with the action above.
3 Check wiring of remote controller.
• Total wiring length: max. 500 m
(Do not use cable x with 3 cores or more.)
• The number of connecting indoor units:
max. 16 units
• The number of connecting remote con-
troller: max. 2 units
If the cause of trouble is not in above 1–3,
4 Diagnose remote controllers.
a) When "OK" is displayed,
Remote controllers have no problem.
Turn the power off, and on again to
check. If abnormality generates 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.
Note: If the unit is not normal after replacing
indoor controller board in group control,
indoor controller board of address "0"
may be abnormal.
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 con-
trollers 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.