Bosch ZSB18 - 2A Installation And Servicing Instructions page 46

46 | Service and spares
Access cover removal
Refer to figure 76.
1. Remove the two pozi-drive screws
2. Remove the access cover
3. Remove the gasket.
Fig. 76 Access cover removal
Cleaning the primary heat exchanger
Refer to figure 77.
B Access the heat exchanger flue ways by inserting the
cleaning brush (7 716 192 312) through the top
access hole in the casing, removal of panel shown in
figure 73.
B Clean heat exchanger flue ways using the cleaning
brush removing any debris from the access point in
the sump.
B Clean around the sealing surface on the sump.
B Replace the access cover.
B Using a suitable container to collect water from
syphon connection at the base of the boiler flush heat
exchanger with water.
B Re-assemble ensuring that the lower baffle (2) and
the top baffle (1) are refitted correctly.
B Refer to figure 74 when re-fitting the burner to ensure
that it fits centrally within the heat exchanger and
location tabs are situated in location holes.
B Ensure that the seal is replaced with a new seal and
ensure that the seal is correctly fitted.
B Check the syphon unit is clean before refitting to
boiler.
B Reassemble and check combustion as stated in
"setting the air/gas ratio" section on page 43.
The heat exchanger does not have to be
removed for cleaning.
The heat exchanger is shown removed from
the boiler to illustrate cleaning more clearly.
6 720 646 195a (2010/11)
3.
2.
1.
1.
6720643895-112.1Wo
Fig. 77 Cleaning heat exchanger
NOTE: Heat exchanger baffles
The baffles (1) and (2) must be refitted into
the heat exchanger in the order shown in
figure 75. Failure to do so may result in
damage to the boiler.
NOTE: CO/CO
2
B If the joint between the air/gas manifold
and heat exchanger is disturbed the
sealing gasket must be replaced .
B After completing the service of the boiler,
the CO/CO must be checked and set to
2
the limits shown in "setting the air/gas
ratio" on page 43.
B When replacing the burner gasket ensure
that the clamping plate is fully tightened
down to the heat exchanger.
Cleaning the syphon
There is no need to remove the syphon to clean.
To drain debris from the syphon, release the clips and
remove the drainage cap from the bottom of the syphon.
Catch the debris and condensate from the syphon into a
suitable container.
AU/NZ
checks