Problem – Too hot
Cause Troubleshooting Remedy
1. The heat pump’s control
computer is not set/adjus-
ted to the customer’s re-
quirements/wishes.
Check the ROOM and CURVE and MIN settings. Adjust incorrect values in the heat pump’s
control computer.
ROOM = Desired indoor temperature.
CURVE = Should be set so that the desired
indoor temperature (ROOM) is maintained
regardless of the outdoor temperature.
MIN = Lowest set-point value on the supply
line regardless of the outdoor temperature.
2. Sensor fault, OUTDOOR/
ROOM/SUPPLY LINE.
Check what the relevant sensor shows. Is it a plausible/
actual value?
Measure the resistance of the sensor, check against the
ohm table in Measurement points .
If the sensor is defective, replace it.
3. Defective 3-way valve mo-
tor.
The motor should set the
valve to the relevant posi-
tion depending on operat-
ing conditions. If it does not,
hot water from the water
heater will mix with the radi-
ator water.
Check the function of the 3-way valve motor by test run-
ning it manually. If the motor does not shift mode during
manual test operation, check that there is voltage to the
motor, see wiring diagram.
Is the motor being supplied with voltage
according to the wiring diagram in both
operating instances?
MANUAL TEST – REV.V. HOT WATER
0=Radiator mode
1=Hot water mode
If there is voltage to the motor but it does
not shift mode, replace it.
4. Jammed reversing valve.
If the valve is not sealed, hot
water from the water heater
will mix with the radiator
water.
Detach the motor and test closing and opening the valve
by turning the shaft by hand.
If it is sluggish or jams, replace with a new
one.
Service Instructions DHP-AQ
VMGFJ202 Danfoss Heating Solutions
26
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