Mitsubishi Electric PUZ-A NHA Series Service Manual page 20

Abnormal point and detection method
Error Code
Pipe temperature thermistor /
Condenser-Evaporator (TH5)
1 The unit is in 3-minute resume protec-
tion mode if short/open of thermistor is
detected. Abnormal if the unit does not
get back to normal within 3 minutes.
(The unit returns to normal operation, if
it has been reset normally.)
2 Constantly detected during cooling, dry-
ing, and heating operation (except
defrosting)
Short: 90:(194˚F) or more
Open: -40:(-40˚F) or less
P9
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.
(Error code : E0)
2 Abnormal if sub-remote controller could
not receive for any signal for 2 minutes.
(Error code: E0)
1 Abnormal if indoor controller board can
E0
not receive any data from remote con-
or
troller board or normally from other
E4
indoor controller board for 3 minutes.
(Error code: E4)
2 Indoor controller board cannot receive
any signal from remote controller for 2
minutes. (Error 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.
(Error code: E3)
2 Remote controller receives transmitted
data at the same time, compares the
data, and when detecting it, judges
E3
different data to be abnormal 30
or
continuous times. (Error code: E3)
E5
1 Abnormal if indoor controller board could
not find blank of transmission path.
(Error code: E5)
2 Indoor controller board receives trans-
mitted data at the same time, compares
the data,and when detecting it, judges
different data to be abnormal 30
continuous times. (Error code: E5)
Cause
1 Defective thermistor
characteristics
2 Contact failure of connector
(CN29) on the indoor controller
board (Insert failure)
3 Breaking of wire or contact
failure of thermistor wiring
4 Temperature of thermistor is
90:(194˚F) or more or -40:
(-40˚F) or less caused by
defective refrigerant circuit.
5 Defective indoor controller
board
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 address "0"
6 Noise has entered into the
transmission wire of remote
controller.
1 2 remote controller are set as
"main." (In case of 2 remote
controllers)
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 trans-
mission wire of remote controller.
20
Countermeasure
1–3 Check resistance value of thermistor.
For characteristics, refer to (P1) above.
2 Check contact failure of connector (CN29)
on the indoor controller board. Refer to 10-7.
Turn the power on and check restart after
inserting connector again.
4 Operate in test run mode and check pipe
<condenser / evaporator> temperature with
outdoor controller circuit board. If pipe
<condenser / evaporator> temperature is
extremely low (in cooling mode) or high (in
heating mode), refrigerant circuit may have
defect.
5 Operate in test run mode and check pipe
<condenser / evaporator> temperature with
outdoor control circuit board. If there is
exclusive difference with actual pipe
<condenser / evaporator> temperature
replace indoor controller board.
There is no abnormality if none of above
comes within the unit.
Turn the power off and on again to operate.
In case of checking pipe temperature
(
with outdoor controller circuit board,
be sure to connect A-control service
tool (PAC-SK52ST).
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. 500m
(Do not use cable o 3 or more)
• The number of connecting indoor units:
max. 16 units
• The number of connecting remote con-
troller: max. 2 units
When the above-mentioned problem 1~3 are not seen.
4 Diagnose remote controllers.
a) When "RC 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 "RC NG" is displayed,
replace remote controller.
c) When "RC E3" is displayed,
d) When "ERC 00-06" is displayed,
[ c),d)→Noise may be causing abnormality. ]
∗ If the unit is not normal after replacing
indoor controller board in group control,
the 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 1
indoor unit.
3 The address changes to a separate setting.
4~6 Diagnose remote controller.
a) When "RC 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 "RC NG" is displayed, replace
remote controller.
c)When "RC E3" or "ERC 00-66" is displayed,
noise may be causing abnormality.
)