Mitsubishi Electric PQRY-P200YEM-A Service Handbook page 90

Note 1 :
• Symptoms of incorrect connection of BC controller pressure sensor to the board
Cooling-only
Normal
Note 2 :
• Check using LED monitor display switch (heat source unit MAIN board SW1)
Note 3 :
• Check CNP1 (liquid measurement) and CMP3 (intermediate) connectors on BC controller board for disconnection or
looseness.
Note 4 :
• With the sensor of the applicable connector removed from the board, use the LED monitor display switch (Note 1) to
check the pressure value.
Pressure Sensor Replacement Precaution
Cooling-principal
Insufficient SC11 large
cooling. SC16 small
PHM < 0
Measured Data
High pressure
Low pressure
BC controller pressure
(liquid measurement)
(intermediate)
(Pressure sensor output voltage)
Symptom
Heating-only
Warm indoor SC SC11 small
small. Warm in- SC16 small
door thermo ON PHM < 0
especially noise.
Signal SW1 Setting
HPS 1 2 3 4 5 6 7 8 9 10
ON
LPS 1 2 3 4 5 6 7 8 9 10
ON
1 2 3 4 5 6 7 8 9 10
PS1
ON
1 2 3 4 5 6 7 8 9 10
PS3
ON
–89–
Heating-principal
Insufficient heating SC11 large
Warm indoor SC small SC16 small
Warm indoor thermo PHM < 0
ON especially noise