Danfoss DHP-AL Installation And Service Instructions Manual page 53

Cause
9. The external auxiliary heater does not start
when the heat pump's control computer
requests it.
10. Closed or partially closed thermostats/
valves in the heating system.
11. The total output of the heat pump and
auxiliary heater is too low in relation to the
building's power demand.
12. Under dimensioned heating system.
13. Changed conditions.
Have you increased your heating and/or hot
water demand?
Problem – Too hot
Cause
1. The heat pump's control computer is
not set/adjusted to the customer's require-
ments/wishes.
2. Sensor fault, OUTDOOR/ROOM/SUPPLY
PIPE.
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.
4. Jammed 3-way valve insert.
If the insert is not sealed, hot water from
the water heater will mix with the radiator
water.
Troubleshooting
If an external auxiliary heater is used, check
that it is correctly installed by test running it
in MANUAL TEST – ADD.HEAT - 1.
If it does not start at manual test operation,
check that the start signal/voltage comes
from the heat pump. See wiring diagram.
Check that the thermostats/valves in the
heating system are open.
What is the building's power demand?
What is the output of the heat pump?
What is the output of the auxiliary heater,
what is it set to?
Check existing heating system.
What output is it dimensioned for to pro-
duce at what supply temperature?
What output is required to keep the room
warm?
• 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 pro-
duction (only applies to VL-systems).
Troubleshooting
Check the ROOM and CURVE and MIN set-
tings.
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.
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.
Detach the motor and test closing and
opening of the valve by pressing the con-
trol arm.
VMBME102
Remedy
Connect the external auxiliary heater accord-
ing to the instructions.
Measure the voltage on the control compu-
ter's probe L2 Oil/Electricity.
Open closed thermostats/valves.
Ensure that available power is at least as
great as the building's power demand.
If the heating system is dimensioned for
greater supply temperatures than the heat
pump can provide, it must be adjusted by
increasing the heat emitting surface for
example.
If the room requires a higher output than
the heating system can provide, extend the
heating system.
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.
Remedy
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
pipe regardless of the outdoor temperature.
If the sensor is defective, replace it.
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.
Take out and clean the jammed insert, or
replace with a new insert.
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