Is the pump current enabled by the
controller?
LED in Lightwheel
®
illuminated? If
not, press the right button. Display
illuminated again?
Does the pump start up in manual
operation?
The solar circuit pump does not work, although the collector is considerably
warmer than the store.
yes no
yes
There is no current; check fuses / re-
place them and check power supply.
The adjusted temperature differ-
ence for starting the pump is too
high; choose a value which makes
more sense.
no
yes
no
Stores cool down at night.
Collector circuit pump runs during
the night?
no yes
Check controller
Check the non-return valves in the
ow and the return pipe for functional
efciency.
Sufcient store insulation?
yes no
Increase insulation.
Insulation close enough to the store?
yes no
Replace insulation or increase it.
Are the store connections insulated?
yes no
Insulate the connections.
Warm water outow upwards?
no yes
Change connection and let the water
ow sidewards or through a siphon
(downwards); less store losses now?
no yes
o.k.
a
Collector temperature at night is
higher than the outdoor temperature.
no yes
Controller might be defective - re-
place it.
Is the pump stuck?
Turn the pump shaft using a screw-
driver; now passable?
Pump is defective - replace it.
yes
no
Does the DHW circulation run for
a very long time?
no yes
Use the circulation pump with timer
and switch-off thermostat energy-ef-
cient circulation).
Circulation pump and blocking valve
should be switched off for 1 night; less
store losses?
yes no
Check whether the pumps of the af-
ter-heating circuit run at night; check
whether the non-return valve is de-
fective; problem solved?
no
Check the non-return valve in
warm water circulation - o.k.
yes no
a
The gravitation circulation in the
circulation line is too strong; insert a
stronger valve in the non-return valve
or an electrical 2-port valve behind
the circulation pump; the 2-port valve
is open when the pump is activated,
otherwise it is closed; connect
pump and 2-port valve electrically in
parallel; activate the circulation again.
Deactivate pump speed control!
Clean or replace it.
Further pumps which are connected
to the solar store must also be
checked.