Mitsubishi Electric PLA-RP1.6AA Service Manual page 64

10-2. SELF-DIAGNOSIS ACTION TABLE
Error Code Meaning of error code and detection method
Abnormality of room temperature
thermistor (TH1)
1 The unit is in three-minute resume
prevention mode if short/open of
thermistor is detected. Abnormal if the
unit does not reset normally after three
minutes. (The unit returns to normal
operation, if it has normally reset.)
2 Constantly detected during cooling,
drying, and heating operation.
Short: 90: or more
P1
Open: -40: or less
Abnormality of pipe temperature
thermistor/Liquid (TH2)
1 The unit is in three-minute resume
prevention mode if short/open of
thermistor is detected. Abnormal if the
unit does not reset normally after three
minutes. (The unit returns to normal
operation, if it has normally reset.)
2 Constantly detected during cooling,
P2
drying, and heating (except defrosting)
operation.
Short: 90: or more
Open: -40: or less
Abnormality of drain sensor (DS)
1 Suspensive abnormality, if short/open of
thermistor is detected for 30 seconds
continuously.
Put off compressor and indoor fan.
2 Short/open is detected for 30 seconds
continuously during suspensive
abnormality.
(The unit returns to normal operation,
if it has normally reset.)
P4
3 Detect the following condition.
• During cooling and drying operation.
• In case that pipe <liquid> temperature
- room temperature <-10deg
(Except defrosting)
• When pipe <liquid> temperature or
room temperature is short/open
temperature.
• During drain pomp operation.
Malfunction of drain pump (DP)
1 Suspensive abnormality, if thermistor of
drain sensor is let heat itself and tem-
perature rises slightly. Put off compres-
sor and indoor fan.
2 Drain pomp is abnormal if the condition
P5
above is detected during suspensive
abnormality.
3 Constantly detected during drain pomp
operation.
Note: Refer to the manual of outdoor unit for the details of display
such as F, U, and other E.
Case
1 Defective thermistor
characteristics.
2 Contact failure of connector
(CN20) on the indoor controller
board. (Insert failure)
3 Breaking of wire or contact
failure of thermistor wiring.
4 Defective indoor controller
board.
1 Defective thermistor
characteristics.
2 Contact failure of connector
(CN21) on the indoor 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 indoor controller board.
1 Defective thermistor
characteristics
2 Contact failure of connector
(CN31) on the indoor controller
board. (Insert failure).
3 Breaking of wire or contact
failure of drain sensor wiring.
4 Defective indoor controller board.
1 Malfunction of drain pump
2 Defective drain
Clogged drain pump
Clogged drain pipe
3 Attached drop of water at the
drain sensor
• Drops of drain trickles from
lead wire.
• Clogged filter is causing
wave of drain.
4 Defective indoor controller board.
64
Judgment and action
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 (CN20) on
the indoor controller board. Refer to 10-6-2.
Put the power on again and check restart
after inserting connector again.
4 Check room temperature display on remote
controller.
Replace indoor controller board if there is
abnormal difference with actual room
temperature.
There is no abnormality if none of above
comes within the unit.
Put the power off, and on again to operate.
1–3 Check resistance value of thermistor.
For characteristics, refer to (P1) above.
2 Check contact failure of connector (CN21) on
the indoor controller board. Refer to 10-6-2.
Put 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 exclusively 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 exclusive
difference with actual pipe <liquid> temperature,
replace indoor controller board. There is no
abnormality if none of above comes within the
unit.
Put the power off, and on again to operate.
1–3 Check resistance value of thermistor.
0: ······6.0k"
10: ····3.9k"
20: ····2.6k"
30: ····1.8k"
40: ····1.3k"
2 Check contact failure of connector (CN31) on
the indoor controller board. Refer to 10-6-2.
Put the power on again and check restart
after inserting connector again.
4 Replace indoor controller board if drain
pump operates with the line of drain sensor
connector CN31-1 and 2 is short-circuited,
and abnormality reappears.
There is no abnormality if none of above
comes within the unit. Put the power off, and
on again to operate.
1 Check if drain-up machine works.
2 Check drain function.
3 Check the setting of lead wire of drain sensor
and check clogs of the filter.
4 Replace indoor controller board if drain
pump operates with the line of drain sensor
connector CN31-1 and 2 is short-circuited
and abnormality reappears.
Refer to 10-6-2.
There is no abnormality if none of above
comes within the unit. Put the power off, and
on again to operate.