14Flow Switch; 15Primary Heat Exchanger - Worcester ZWBR 7-28 HE plus Installation And Servicing Instructions

9.3.14 Flow switch
y Shut the mains water inlet valve and drain the domes-
tic hot water circuit.
y Pull-off the connectors from the micro-switch.
y Unscrew the inlet and union connection and remove
the assembly.
y Reset the domestic hot water flow rate on the new
assembly.
INLET
6 720 610 602 - 05.10
Fig. 58
9.3.15 Primary Heat Exchanger
y Drain the appliance.
y Check that the gas supply is turned off.
y Check that the appliance is electrically isolated.
y Remove the fan assembly complete with the gas/air
tube and mixer assembly. Refer to section 9.3.2.
y Remove the burner. Refer to section 9.2.
y Disconnect the sensors. Refer to section 9.3.6.
y Undo the central heating flow union.
y Undo the top connection of the pump. Refer to
fig. 57.
y Undo the grey plastic cap, next to the top pump con-
nection at the base of the heat exchanger.
y Unscrew and remove the condensate trap. Refer to
section 9.2.
y Unscrew and remove the two screws securing the
heat exchanger top bracket to the rear panel.
y Lift up the flue duct, item 271, refer to fig. 2.
6 720 610 597 GB (01.07)
y Pull forward from the top and lift the heat exchanger
from the casing.
y Transfer components, as necessary, to the new heat
exchanger.
y Ensure that all the seals are in place and all of the
connections are tight before re-commissioning the
appliance.
OUTLET
6 720 610 602 - 06.10
Fig. 59
Maintenance
45