Danfoss Heat Pump Troubleshooting Manual page 26

Troubleshooting Guide
Defective G2 shunt (HGW)
Action:
Check the function of the HGW shunt by test running it manually.
If the motor does not shift mode during manual test operation, check
that there is voltage to the motor.
Terminal 221 brown/N (- signal open to RAD) 230Vac
Terminal 222 black/N (+ signal open to HW) 230Vac
Remember to measure with and without load. (With and without motor connected to the relay card)
Use multimeters with buzzer to fault trace the cable between the control card and the shunt.
If there is voltage to the motor and the motor shifts mode as it should, replace the 3-way.
If there is voltage to the motor but the shunt motor does not shift mode, replace the motor.
If there is no voltage to the shunt motor replace the circuit card or the cable.
The HGW shunt shifts from the one end position to the other in 30 seconds and the total voltage time is approx 35 secs.
26
Thermal comfort
The voltage for the HGW shunt
VMIFB202
is measured here