Buderus 500 - 28/C Servicing Manual page 45

box 85 Check the non return valve
A
Remove the fan, see box 76 to box 79.
Check to see if the non return valve (item 5 and 6, if fitted)
is soiled or defective.
Loosen the upper nut (item 2).
Loosen the two lower nuts (item 1).
Turn the securing plate 180° counterclockwise (item 3).
Remove the fan part (item 7).
Bend the silicon seal (item 4).
Remove the plastic valvehousing (item 5).
Check the silicon valve (item 6) and replace when
necessary.
After checking, refit all components in reverse order.
Make sure that the cam (item A) of the silicon valve is
mounted in the correct manner (A).
First tighten the upper nut (item 2), then tighten the lower
two nuts (item 1).
Refit all other components in reverse order, then put the
boiler into service, see box 51, 54 or 55.
box 86 Check the Venturi
Take the boiler out of operation, see box 43, 44 or 47.
Remove the air intake duct, see box 77.
Remove the Venturi, see box 81, item 1.
We reserve the right to make technical modifications
Servicing manual Gas condensing boiler Buderus 500-24/S, 500-24/C and 500-28/C • Issued 02/2006
6
5
4
3
7
2
1
box 87
1
Check the article number of the Venturi against those
listed in the table in box 5.
Check to ensure that the correct Venturi has been fitted.
This is done by comparing the article numbers listed
against the number on the Venturi (item 1), see box 5.
Check the Venturi for soiling.
box 88
Refit the Venturi and fan by following the above procedure
in reverse order.
Refit the air silencer tube.
Refit the casing and place the boiler into operation,
see box 51, 53, 54 or 55.
box 89 Check the pump – mechanical restrictions
Remove casing, see box 47.
Remove the vent screw on the front of the pump,
A
see box 57.
CAUTION!
Note that water will squirt out when the vent screw is
removed. Have a bucket and a supply of dry cloths to
hand.
box 90
Put the electrical system of the boiler into operation,
see box 54 and 55.
Check to see if the pump is running. The pump may
become mechanically blocked if the heating system has
been out of use for an extended period.
Insert a screwdriver and attempt to make the pump turn.
Use the screwdriver to turn the fan wheel in the direction
of rotation shown on the identification plate of the pump.
Refit the vent screw to the pump.
Fit casing, see box 51.
Buderus Ltd. • http://www.buderus-domestic.co.uk
Actions 7
1
45