Danfoss DHP-H, Installation And Service Instructions Manual

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77
VMBMA602
Cause Troubleshooting Remedy
13. Changed conditions.
Have you increased your heating and/or hot
water demand?
• If the heat pump has been dimensioned
for a certain demand and this demand is
increased, the heat pump might not be able
to maintain the desired room temperature.
• If hot water consumption increases, a
larger proportion of time is used to produce
hot water, which means less time for heat
production (only applies to VL-systems).
If the heat pump cannot cope with the
demand, replace it with one with a higher
output or supplement it with a higher out-
put auxiliary heater.
Problem – Too hot
Cause Troubleshooting Remedy
1. The heat pump’s control computer is
not set/adjusted to the customer’s require-
ments/wishes.
Check the ROOM and CURVE and MIN set-
tings.
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 the Measurement
points section.
If the sensor is defective, replace it.
3. Defective 3-way valve motor. The motor
should set the valve to the relevant end
position depending on operating condi-
tions. If it does not, hot water from the
water heater will mix with the radiator
water.
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 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 – VXV HOT WATER
0=Radiator mode, arm out from valve.
1=Hot water mode, arm positioned towards
the valve.
If there is voltage to the motor but the arm
does not shift mode, replace it.
4. Jammed 3-way valve insert.
If the insert is not sealed, hot water from
the water heater will mix with the radiator
water.
Detach the motor and test closing and
opening of the valve by pressing the con-
trol arm.
Take out and clean the jammed insert, or
replace with a new insert.