10.4.6 Other
Table 33. Problem – The heat pump runs and runs but never stops
Cause Troubleshooting Remedy
1. Air in the heating system. Listen for air in the heat pump and heat-
ing system.
Bleed the heating system according to
the installation instructions.
2. Lack of refrigerant, not enough
refrigerant in the system.
Using manometer apparatus and ther-
mometer, check that the unit’s overheat-
ing is correct for the specific refrigerant.
Follow the correct procedure (depend-
ing on type of refrigerant) to add the cor-
rect amount of refrigerant.
If there appears to be a leak in the refrig-
erant circuit, carry out leak tracing and
any necessary corrective action. If leak
tracer is not available, brush soap water
on the suspected leak and look for bub-
bles. Also check for oil as this can come
out from the refrigerant circuit.
3. Changed conditions Have you
increased your heating and/or hot
water demand?
•
If the heat pump has been dimen-
sioned 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.
If the heat pump cannot cope with the
demand, replace it with one with a
higher output or supplement it with a
higher output auxiliary heater.
Table 34. Problem – Runs on electric heating element
Cause Troubleshooting Remedy
1. Operating mode AUX. HEATER is
selected.
If this operating mode is selected, the auxil-
iary heater is used for heating and hot
water production, not the compressor.
If AUX. HEATER mode is selected and
you no longer want it, change to AUTO,
the heat pump then controls both the
compressor and auxiliary heater.
2. The compressor cannot run due to
an alarm.
Check the alarm that is indicated in the dis-
play.
Rectify the problem and rest the alarm.
See Operational problems.
3. The integral value has reached the
start level for the auxiliary heater.
Check what the integral value is in the con-
trol system.
If the auxiliary heater is in operation
because the integral value has counted
down to the start value, the computer
reacts as it should, see(missing heading
target)for more information.
4. Peak heat operation (anti-legion-
ella function) is running.
Check if the heat pump runs peak heat. See
the instructions for the relevant model.
Peak heat operation occurs in connec-
tion with hot water production with the
set interval. The compressor should then
start to produce hot water and 2
minutes later the auxiliary heater starts.
The compressor must then stop and the
stop temperature be reached with only
the auxiliary heater connected. Take no
corrective action.
5. The heat pump has stopped on
HIGH RETURN.
•
Check what the MAX RETURN value is
set at in the heat pump’s control com-
puter. It must be adjusted to the unit’s
maximum supply temperature and the
system’s delta temperature so that it
does not cut at too high a return tem-
perature when the highest supply
temperature is transmitted.
•
Check what the return line sensor
shows. Is it a plausible/actual value? If
not, take a resistance reading from the
sensors and check against the ohm
table in Measurement points.
If the MAX RETURN value is not adjusted
for the system according to the trouble-
shooting window, adjust it.
If the sensor is defective, replace it.
54 – Service instructions VMGFC302
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