Wilo Star AC Series, Installation And Operating Instructions Manual, Page: 12 / 18

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ENGLISH
6 Operation
System filling and venting
The pump may need venting e.g. if the
heating and pump are working but the
heating element remains cold. If there
is air in the pump chamber, the pump
will not pump water.
Carefully fill the unit with water.
Solar thermal systems must be filled
with ready for use mixtures. The pump
must not be used to mix the medium
in the system.
The pump is normally vented automa-
tically after a short operatinal period.
Short-term dry running will not dama-
ge the pump. If it becomes necessary
to vent the pump, please observe the
following procedure:
– Switch off pump,
Risk of burning if the pump
is touched!
Depending on the operating
condition of the pump and/or
installation (fluid temperature)
the pump/motor can become
very hot.
– Close the valve on the discharge
side.
Risk of scalding!
Depending on the fluid tem-
perature and the system pres-
sure, if the vent screw is com-
pletely loosened hot liquid or
vapour can escape or even
shoot out at high pressure.
– Carefully loosen and fully remove
the vent plug with a suitable
screwdriver (Fig. 9).
– Carefully push pump shaft back
several times with screwdriver.
– Protect all electrical parts against
the leaking water.
– Switch-on pump.
It is possible that the
pump blocks with the
vent plug open, de-
pending on the system
pressure.
– After 15...30 s tighten the vent plug.
– Re-open isolating valve,
Speed setting
If the rooms cannot be sufficiently
heated, the speed of the pump may be
too low. In this case you will need to
switch to a higher speed.
If, on the other hand, the pump is set
at too high a speed, flow noise may
occur in the lines and in particular at
throttled thermostatic valves. This can
be rectified by switching to a lower
speed.
The speed is changed by means of
a rotary button at the terminal box.
3 represents the lowest and 1 the
highest speed.
7 Maintenance
Prior maintenance or repair
work switch off the pump and
secure against unauthorized
switching.
ATTENTION!