3.5.5
Heating comfort
Problem – Too cold
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 MAX 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.
MAX = Highest set-point value on the sup-
ply line regardless of the outdoor tempera-
ture.
2. Incorrect operating mode
set in the heat pump’s con-
trol computer.
Check which operating mode is set.
If the incorrect operating mode is set,
change to the desired operating mode.
3. Sensor fault, OUTDOOR/
ROOM/SUPPLY LINE/
RETURN 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.
4. The 3-way valve has jam-
med in hot water mode.
1. Check the function of the 3-way valve motor by test
running it manually. If the motor does not shift mode
during manual test operation, check that there is volt-
age to the motor, see wiring diagram.
2. Detach the motor and test closing and opening the
valve by turning the shaft by hand.
Is the motor being supplied with voltage
according to the wiring diagram in both
operating instances?MANUAL TEST – REV.V.
HOT WATER 0=Radiator mode1=Hot water
modeIf there is voltage to the motor but it
does not shift mode, replace it.
5. Defective electric heating
element.
Use a buzzer and check if all coils in the electric heating el-
ement are intact.
If the electric heating element is defective,
replace it.
6. The heat pump has stop-
ped on HIGH RETURN.
▪
Check what the MAX RETURN value is set at in the
heat pump’s control computer. It must be adjusted to
the unit’s maximum supply temperature and the sys-
tem’s delta temperature so that it does not cut at too
high a return temperature when the highest supply
temperature is transmitted.
▪
Check what the return line sensor shows. Is it a plausi-
ble/actual value? If not, take a resistance reading from
the sensors and check against the ohm table in Meas-
If the MAX RETURN value is not adjusted for
the system according to the troubleshoot-
ing window, adjust it.
If the sensor is defective, replace it.
7. Heat production is stop-
ped by the HYSTERESIS
function.
If the flow temperature rises as soon as heat production is
stopped by HYSTERESIS before INTEGRAL reaches 0, there
may be heating deficit in the house.
▪
Check if heat production stops because the hysteresis
value is set too low? (See the installation instructions
for factory setting.)
▪
Check if heat production stops because thermostats/
valves in the heating system are closed or partially
closed?
▪
Check if heat production stops because the heating
system is under dimensioned?
▪
Try increasing the hysteresis value un-
til the heat pump stops on INTEGRAL
instead.
▪
Open thermostats/valves in the heat-
ing system and check that the heat
pump stops on INTEGRAL.
▪
If the heating system is deemed to be
under dimensioned, the system must
be extended (the heat emitting sur-
face increased).
Service Instructions
DHP-AQ
VMGFJ202
Danfoss Heating Solutions
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