Worcester benchmark ZWB 7-25 R 25 HE Design, Installation And Servicing Instructions page 36

Maintenance
B Loosen any deposits in the heat exchanger from top
to bottom using the cleaning blade. Refer to fig. 52.
Fig. 52
B Clean the heat exchanger from top to bottom using
the brush. Refer to fig. 53.
Fig. 53
B Flush the heat exchanger from the top. Refer to
fig. 54.
B Clean out the condensate collector and trap connec-
tion (with other end of brush).
Fig. 54
B Refit the clean-out cover using a new seal and
tighten screws to torque of approx. 5 Nm.
36
6 720 610 332-73.1R
6 720 610 332-74.1R
6 720 610 332-75.2R
Burner
B Check that the gas cock is turned off and the master
switch is in the OFF position
B Remove the clips (1) and unscrew the two bolts (2).
Refer to fig. 55.
B Unscrew and remove the two hexagon screws secur-
ing the fan (3).
B Slacken fully the rear securing bolt (4).
B Remove the burner coverplate.
2.
3.
1.
Fig. 55
B Remove the burner skin and clean components. Do
not use a wire brush. Refer to fig. 56.
Fig. 56
B Re-assemble burner in reverse order inspect seal for
damage and replace if necessary.
B Adjust gas/air ratio. Refer to section 7.2.
4.
7 181 465 330-04.1R
7 181 465 330-09.2R
6 720 611 441 GB (03.11)