Mitsubishi Electric PUHZ-W50VHA Technical Manual page 40

SELF-DIAGNOSIS ACTION TABLE
Error Code Abnormal point and detection method
Target Temperature thermistor (TH1)
1 The unit is in 3-minute resume
prevention mode if short/open of
thermistor is detected. Abnormal if the
unit does not reset normally after 3
minutes. (The unit returns to normal
operation, if it has been reset normally.)
2 Constantly detected during cooling,
drying, and heating operation.
Short: -90: or more
Open: -40: or less
P1
Pipe temperature thermistor/Liquid
(TH2)
1 The unit is in 3-minute resume
prevention mode if short/open of
thermistor is detected. Abnormal if the
unit does not reset normally after 3
minutes. (The unit returns to normal
operation, if it has been reset normally.)
2 Constantly detected during cooling,
drying, and heating (except defrosting)
P2
operation
Short: 90: or more
Open: -40: or less
Pipe temperature thermistor / 2-phase
(TH5)
1 The unit is in 3-minute resume protection
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,
drying, and heating operation (except
defrosting)
Short: 90: or more
Open: -40: or less
P9
Error code indication
You can check an error code on both 1 and 2.
1 LCD display on remote controller
2 2-digit LED indicator on outdoor unit PCB
(For SPLIT type outdoor unit, this LED indicator is optional parts.PAC-SK52ST)
* The 2-digit LED indicator on outdoor unit PCB can display indoor side error as well.
Cause
1 Defective thermistor
characteristics
2 Contact failure of connector on
the interface controller board
(Insert failure)
3 Breaking of wire or contact
failure of thermistor wiring
4 Defective interface controller
board
1 Defective thermistor
characteristics
2 Contact failure of connector on
the interface controller board
(Insert failure)
3 Breaking of wire or contact
failure of thermistor wiring
4 Defective refrigerant circuit is
causing thermistor temperature
of 90: or more or -40: or
less.
5 Defective interface controller
board
1 Defective thermistor
characteristics
2 Contact failure of connector on
the interface controller board
(Insert failure)
3 Breaking of wire or contact
failure of thermistor wiring
4 Temperature of thermistor is
90: or more or -40: or less
caused by defective refrigerant
circuit.
5 Defective interface controller
board
40
Countermeasure
1–3 Check resistance value of thermistor.
0: 15.0k"
10: 9.6k"
20: 6.3k"
30: 4.3k"
40: 3.0k"
If you put force on (draw or bend) the lead wire
with measuring resistance value of thermistor,
breaking of wire or contact failure can be
detected.
2 Check contact failure of connector on the
interface controller board.
Turn the power on again and check restart
after inserting connector again.
4 Check <target> temperature display on
remote controller.
Replace interface controller board if there is
abnormal difference with actual <target>
temperature.
Turn the power off, and on again to operate
after check.
1–3 Check resistance value of thermistor.
For characteristics, refer to (P1) above.
2 Check contact failure of connector on the
interface controller board.
Turn the power on and check restart after
inserting connector again.
4 Check pipe <liquid> temperature with remote
controller in test run mode. If pipe <liquid>
temperature is extremely low (in cooling
mode) or high (in heating mode), refrigerant
circuit may have defective.
5 Check pipe <liquid> temperature with
remote controller in test run mode. If there is
extremely difference with actual pipe <liquid>
temperature, replace interface controller
board.
Turn the power off, and on again to operate
after check.
1–3 Check resistance value of thermistor.
For characteristics, refer to (P1) above.
2 Check contact failure of connector on the
interface controller board.
Turn the power on and check restart after
inserting connector again.
4 Operate in test run mode and check pipe
<2-phase> temperature with outdoor
controller circuit board. If pipe <2-phase>
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
<2-phase> temperature with outdoor control
circuit board. If there is
extreme difference with actual pipe
<2-phase> temperature, replace interface
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).
)