Mitsubishi Electric City Multi CMB-P1016NU-G, Service Handbook

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[
IX
Troubleshooting ]
Note1 BC controller: Phenomena when the pressure sensor is connected wrongly (reverse connection of P1 and P3) to the
board.
Note2 Check the self-diagnosis switch (Heat source unit control board SW1).
Note3 Check whether CNP1 (liquid side) connector on the BC controller control board and the connector CNP2 (intermedi-
ate part) are not disconnected or not loose.
Note4 Check the pressure value on the self-diagnosis switch (same as note1) with the connector of the applied pressure
sensor is disconnected from the board.
Cooling-only Heating only Heating main
Non-cooling
Indoor heating SC small
Heating indoor Thermo ON
Especially noise is large.
Indoor heating SC small
Heating indoor Thermo ON
Especially noise is large.
Cooling-main
Symptoms
SC11 large
SC16 small
PHM large
SC11 large
SC16 small
PHM large
Non-cooling Normal SC11 large
SC16 small
PHM large
Measurement data SW1 setting value
Heat source unit
high pressure
Heat source unit
low pressure
BC controller pressure
(liquid side)
BC controller pressure
(intermediate part)
Symbol
63HS
P1
63LS
P3
1 2 3 4 5 6 7 8 9 10
ON
1 2 3 4 5 6 7 8 9 10
ON
1 2 3 4 5 6 7 8 9 10
ON
1 2 3 4 5 6 7 8 9 10
ON