Bosch Worchester GREENSTAR ZWB 7-27 HE combi Installation And Servicing Instructions page 35

B Loosen any deposits in the heat exchanger from top
to bottom using the cleaning blade. Refer to fig. 51.
Fig. 51
B Clean the heat exchanger from top to bottom using
the brush. Refer to fig. 52.
Fig. 52
B Remove the fan and the burner (see section headed
"Burner") and flush the heat exchanger from the top.
B Clean out the condensate collector and trap connec-
tion (with other end of brush).
2.
Fig. 53
B Refit the clean-out cover using a new seal and
tighten screws to torque of approx. 5 Nm.
6 720 610 576 GB (02.05)
6 720 610 332-73.1R
6 720 610 332-74.1R
1.
6 720 610 332-75.1R
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. 54.
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.
1.
Fig. 54
B Remove burner and clean components. Do not use a
wire brush. Refer to fig. 55.
Fig. 55
B Re-assemble burner in reverse order using a new
seal.
B Adjust gas/air ratio. Refer to section 7.2.
Maintenance
4.
3.
7 181 465 330-04.1R
7 181 465 330-08.1R
35