Cause
Troubleshooting
Remedy
11. Overfilled refrigerant cir-
cuit.
Using manometer apparatus and thermometer, check that
the unit’s overheating is correct for the specific refrigerant.
Follow the correct procedure (depending
on type of refrigerant) to add the correct
amount of refrigerant.
12. 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 tem-
perature.
▪
If hot water consumption increases, a larger propor-
tion of time is used to produce hot water, which
means less time for heat production.
If the heat pump cannot cope with the de-
mand, replace it with one with a higher
output or supplement it with a higher out-
put auxiliary heater.
Problem – Auxiliary heater cuts in too soon
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, CURVE, INTEGRAL A1 and INTEGRAL A2
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 tem-
perature. INTEGRAL A1 = Start value for the
compressor. INTEGRAL A2 = Start value
(calculated from A1) for the auxiliary heater.
2. 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 tem-
perature.
▪
If hot water consumption increases, a larger propor-
tion of time is used to produce hot water, which
means less time for heat production.
If the heat pump cannot cope with the de-
mand, replace it with one with a higher
output or supplement it with a higher out-
put auxiliary heater.
3. Lack of refrigerant, not
enough refrigerant in the
system.
Using manometer apparatus and thermometer, check that
the unit’s overheating is correct for the specific refrigerant.
If there appears to be a leak in the refriger-
ant circuit, carry out leak tracing and any
necessary corrective action. If leak tracer is
not available, brush soap water on the sus-
pected leak and look for bubbles. Also
check for oil as this can come out from the
refrigerant circuit.
Problem – Short operating times despite heating demand
Cause
Troubleshooting
Remedy
ROOM and/or CURVE set too
high in combination with a
heating system with poor
circulation due to closed ra-
diator valves, too small ele-
ments or insufficient water
volume. A tight fitting sys-
tem with poor pipe dimen-
sions may produce the same
phenomena.
Check if the heat pumps starts, if the supply temperature
rises quickly whilst nothing happens to the return temper-
ature. If this happens and the heat pump is stopped by the
hysteresis function to later quickly drop in temperature
(supply) in order to start again, but cannot due to time
conditions in regulation, this means that the heat pump
cannot transport the heat away from the condenser as it
should. In such a case, hysteresis starts and stops the heat
pump often.
Adjust ROOM and CURVE if necessary. En-
sure that there is sufficient flow over the
condenser and the heating circuit.
Problem – Connection of external AH
Cause
Troubleshooting
Remedy
Incorrectly connected auxili-
ary heater. Does not start
when the control computer
gives the signal.
Check the connection against the instructions/wiring dia-
gram. Test the function in manual mode.
If the auxiliary heater is incorrectly connec-
ted, reconnect according to the instruc-
tions.
Service Instructions
DHP-AQ
VMGFJ202
Danfoss Heating Solutions
32
