Maintenance; Fault Finding; Causes And Remedies - Wilo -Star-Z 20/1 Installation And Maintenance Instructions Manual

not harm the pump. If necessary,
the pump can be directly vented in
accordance with the following proce-
dure:
– Switch-off pump,
– close discharge isolating valve,
– Carefully slacken and remove the
central access plug using screw-
driver (Fig. 3).
– Depending on liquid tempe-
rature and system pressure,
hot liquid or vapour can be
releases when undoing the
central access plug.
Beware!
Danger of scalding!
(Only when used for hot
water heating).
– Protect electrical parts from leaking
water,
– switch-on pump again,
– after 15 ... 30 secs close access
plug again,
– open isolating valve again.
ATTENTION!
It is possible that the
pump shaft jams with
the access plug open,
depending on system
pressure.
– The pump can become
extremely hot, depending
on the operating state of
pump or pipe system (fluid
temperature).
Beware of scalding when
touching the pump!
(Only when used for hot
water heating).
6.2 Pre-Start Adjustments
– Direction of rotation check on
3-phase motors:
Remove central access plug at the
non-drive end of the motor. Briefly
switch on motor and check
whether sense of rotation corre-
sponds to the arrow on the name
plate; if necessary, change any two
phase wires.

7. Maintenance

Prior maintenance or repair
work switch off the pump and
secure against unauthorized
switching.
8. Fault Findings –

Causes and Remedies

8.1 Pump is switched on, but
fails to run:
– Check power supply fuses.
– Check voltage at pump terminals
(refer to name plate data).
– Check capacitor size (refer to name
plate data!).
– Rotor shaft has jammed, e.g. by
incrustations.
Remedy: Remove central access
plug, check free movement of shaft
or free respectively at the slotted
shaft end by means of a screw-
driver.
ENGLISH
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