Cause
Troubleshooting
Remedy
4. The 3-way valve has jammed 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
voltage to the motor, see wiring
diagram.
2.
Detach the motor and test clos-
ing 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 mode
1=Hot water mode
If 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 element are intact.
If the electric heating element is defec-
tive, replace it.
6. The heat pump has stopped 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 temper-
ature and the system’s delta tem-
perature so that it does not cut at
too high a return temperature
when the highest supply tempera-
ture 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, Page 11.
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.
7. Heat production is stopped by the
HYSTERESIS function.
If the flow temperature rises as soon as
heat production is stopped by HYSTERE-
SIS 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 parti-
ally closed?
•
Check if heat production stops
because the heating system is
under dimensioned?
•
Try increasing the hysteresis value
until the heat pump stops on INTE-
GRAL instead.
•
Open thermostats/valves in the
heating 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 emit-
ting surface increased).
8. The auxiliary heater is not permitted
to cut in with sufficient output.
Value set too low on MAXSTEP.
MAXSTEP 1 = 3 kW
MAXSTEP 2 = 6 kW
MAXSTEP 3 = 9 kW
MAXSTEP 4 = 12 kW
MAXSTEP 5 = 15 kW
Check the set value on MAXSTEP in the
heat pump’s control computer.
If necessary, adjust the MAXSTEP value
in the heat pump’s control computer.
230V 1-N MAXSTEP 1 – 3
400 V 3-N: MAXSTEP 1 – 5
MAXSTEP 1 = 3 kW
MAXSTEP 2 = 6 kW
MAXSTEP 3 = 9 kW
MAX STEP 4 = 12 kW (cannot cut in
when the compressor is running.)
MAX STEP 5 = 15 kW (cannot cut in
when the compressor is running.)
9. The external auxiliary heater does not
start when the heat pump’s control
computer requests it.
If an external auxiliary heater is used,
check that it is correctly installed by test
running it in MANUAL TEST –
EXT.AUX.HEATER - 1.
If it does not start at manual test opera-
tion, check that the start signal/voltage
comes from the heat pump. See wiring
diagram.
Connect the external auxiliary heater
according to the instructions.
Measure the voltage on the I/O card’s
probe L2 Oil/Electricity.
Service instructions VMGFJ102 – 25
