Worcester 26CDi XTRA Installation And Servicing Instructions page 32

25. Secondary Heat Exchanger. See figs. 32, 33, 34, 35, 36, 37,
39, and 43.
Check that the electricity supply to the appliance is turned off.
Drain the central heating circuit as described in Section 14.2 (a).
The secondary high efficient heat exchanger is housed in a
stainless steel box. The assembly is located inside and at the rear
of the inner casing.
Fig. 43. Secondary Heat Exchanger
Remove screw securing
bracket to flue bend
Remove top screw securing
heat exchanger to inner
casing
Slacken the screw in the
clip securing the flue bend
to the top of the heat
exchanger.
Ease the bend clear of
inner casing.
Remove the sealing gasket.
Disconnect the plastic drain
pipe to the condensate trap.
To access the assembly:
i) Remove the inner casing cover, fan, flue hood assembly and
disconnect the overheat thermostat as described in
Section 13.3 (b), (e), (f) and Section 14.3 (4).
ii) Remove the combustion chamber front and sides assembly
and unhook the securing rods out of the locations in the inner
casing as described in Section 13.3 (g).
iii) Remove the gas to water heat exchanger, rear fibre insulation
pad and burner assembly as described in Section 14.3 (5), (6)
and (7).
iv) Unscrew the three screws either side of the inner casing
securing the rear of the combustion chamber to the inner casing
and remove.
v) Slacken the screw in the clip securing the flue bend to the top
of the heat exchanger. Ease the bend out of the appliance.
vi) Remove gas valve section 14.3 (c).
vi) Remove the screw located on top of the inner casing.
Retain all components removed from the appliance.
Remove the
top screw
Fan outlet spigot
NB: A quantity of primary
water will remain in the heat
exchanger
To remove the assembly:
i) Remove the top screw securing the heat exchanger to the inner
casing. Retain the screw.
ii) Pull off the two clips securing the flow and return pipes to the
heat exchanger located under the inner casing. Ease the 'O' ring
connections just clear of the fittings.
Warning: A quantity of primary water will remain in the heat
exchanger and pipework.
iii) Unscrew the two union lock nuts securing the flow and return
connections to the inner casing.
iv) Disconnect the plastic drain pipe to the condensate trap.
v) Ease the assembly out of the locations in the base of the inner
casing and clear of the appliance.
If a blockage is suspected the stainless steel box may be flushed
out with clean water and reassembled.
Alternatively discard the assembly and sealing gasket and
replace with a new assembly.
32
Inner casing
Secondary
heat exchanger
To access the secondary
heat exchanger remove
the three screws either
side of the inner casing
and remove the rear of
the combustion chamber.
Rear of combustion
chamber
Unscrew the locknuts
securing the flow and return
connection.
Pull off the clips from the flow
and return connections. Ease
the 'O' ring connections just
clear of the fitting.