Mitsubishi Electric PURY-P72 Service Handbook page 317

[ IX Troubleshooting ]
Check whether the BC board output signal corresponds with the solenoid valve operation correspond.
1) SVA, SVB, SVC
SVA, SVB, and SVC turn on or off according to the indoor unit operation mode.
Port
SVM1 and SVM2
SVM1 and SVM2 turn on or off according to the indoor unit operation mode.
Operation
Cooling only
mode
SVM1
SVM2
2) SVA, SVB, SVC
Measure the temperature at the upstream and downstream pipes
Measure the temperature at the upstream and downstream
HWE1116D
Cooling
SVA ON
SVB OFF
SVC ON
Cooling main Heating only
Pressure dif-
ferential con-
ON
trol OFF or
ON
Pressure dif-
ferential con-
OFF OFF
trol OFF or
- 308 -
Mode
Heating Stopped
OFF OFF
ON OFF
OFF OFF
Heating main
OFF OFF
Pressure dif-
ferential con-
trol OFF or
ON ON
and of SVA.
pipes and of SVB.
Defrost Fan
OFF OFF
OFF OFF
OFF ON
Defrost Stopped
ON OFF
OFF OFF
GB