Worcester ZWBR 7-28 HE plus Installation And Servicing Instructions page 40

Maintenance
Condensation trap
In order to prevent spillage of condensate the conden-
sation trap should be completely removed, (see
page 38, fig. 45).
y Unscrew condensation trap and check connection to
heat exchanger is clear.
y Remove condensation trap cover and clean.
y Fill condensation trap with approx. 1/4 l of water and
refit.
Electrode assembly
y Switch off the master switch.
y Pull off the leads from the electrodes. Refer to fig. 2.
y Unscrew the two fixing screws and carefully remove
the electrode assembly . Refer to fig. 44.
y Clean the electrodes with a non-metallic brush. (The
spark gap should be 4.5 mm ± 0.5 mm.)
y Replace and re-connect the assembly taking care not
to mislay the inspection window.
Siphon
y Unscrew the clip and disconnect the pipe to the
siphon.
y Remove the yellow plug to drain the siphon.
y Unscrew the securing nut from beneath the side
facia and remove the siphon. Refer to figure below.
y Refit and prime the siphon.
Condensate
Drain
Siphon
Fig. 51
40
Expansion vessel
The expansion vessel should be checked once a year.
y Depressurise appliance.
y If necessary, adjust expansion vessel charge pres-
sure to static head of the heating system.
Heating system pressure
i
y The pointer on the pressure gauge should be 1 bar.
y If the pointer is below 1 bar (when the system is
cold), water should be added until the pointer is
1 bar again.
y Max. pressure of 2.5 bar when the heating system
water is at maximum temperature must not be
exceeded. If this pressure is exceeded then an extra
expansion vessel must be fitted in the system return
as close to the appliance as possible.
y If the system does not retain the pressure, the expan-
sion vessel and the heating system should be
checked for leaks.
6 720 610 602 - 16. 1O
Fill the system using the WRc approved
filling loop.
6 720 610 597 GB (01.07)