Mitsubishi Electric PURY-P200 Service Handbook page 173

Note1 BC controller: Phenomena when the pressure sensor is connected wrongly (reverse connection of P1 and P3) to the board.
Cooling-only
Normal Non-cooling
Note2 Check the self-diagnosis switch (Outdoor control board SW1).
Measurement data Symbol
Outdoor high-pressure
pressure
Outdoor low-pressure
pressure
BC controller pressure
(liquid side)
BC controller pressure
(intermediate part)
Note3 Check whether CNP1 (liquid side) connector on the BC controller control board and the connector CNP2 (in-
termediate part) are not disconnected or not loose.
Note4 Check the pressure value with the self-diagnosis switch (same as note1) with the connector of the applied
pressure sensor is disconnected from the board.
(2) Temperature sensor
Pull out the applied thermistor connector from the board
Measure the temperature of the applied thermistor.
Compare the temperature to the thermistor resistance and the act-
ual measurement value, and check whether there is no difference.
Insert the connector of the applied thermistor to the board,
check the sensor inlet temperature with the LED monitor,
and check the temperature difference.
Phenomena
Cooling-main
SC11 large Heating indoor
SC16 small SC small
PHM large Heating indoor
Thermo ON
Especially noise
is large.
SW1 setting value
1 2 3 4 5 6 7 8 9 10
63HS
ON
1 2 3 4 5 6 7 8 9 10
63LS
ON
1 2 3 4 5 6 7 8 9 10
P1
ON
1 2 3 4 5 6 7 8 9 10
P3
ON
Thermistor troubleshooting instruction
Start
(actual measurement value)
Check the resistance of the thermistor.
No temperature difference
YES
No temperature difference
YES
Normal
- 170 -
Heating-only
SC11 large Non-cooling
SC16 small Heating indoor
PHM large SC small
Heating indoor
Thermo ON
Especially noise
is large.
Note1
Note2
Note3
NO
Replace the thermistor.
Note4
NO
Check for contact failure.
Replace the control board.
Heating-main
SC11 large
SC16 small
PHM large