Worcester GREENSTAR HIGHFLOW 440CDi Instruction Manual page 46

A
B
C
D
44
REPLACEMENT PARTS
E
1
2
G
4
3
REPLACEMENT PARTS
Domestic hot water heat exchanger:
Before removing the heat exchanger, close
the inlet valves, drain the hot water circuits
and tank.
The pipe (A) may be removed between the
flow sensor outlet and the plate heat exchanger
to improve access to the rear connections.
Undo the two screws securing the plastic
housing to the heat exchanger.
Remove the heat exchanger.
To refit, follow the above in reverse. Ensure
any seals that have been disturbed are
replaced.
Pressure gauge:
Drain the appliance.
Unscrew connection to the pressure relief valve.
Remove 2 screws from rear of control
panel and remove pressure gauge.
Replace sealing washer and replace
pressure gauge.
Expansion vessel:
Drain the appliance.
Move control panel into service position.
Remove locking screw (C) from vessel
bracket.
Hinge pressure vessel out and lift from
brackets.
Undo the union connection at the top of
the vessel.
Set the pressure of the new vessel to that
required by the system.
Pressure relief valve:
F
Drain the appliance.
Disconnect drain pipe from valve (D)
Undo nut retaining valve to flow pipe.
Undo nut connecting pressure gauge.
Remove valve.
Replace sealing washer and fit a new valve.
Condensate trap:
Move control and pressure vessel into
service position.
Remove inner case door.
Remove condensate pump.
Remove access panel (E) at the base of
the inner casing.
Remove screw retaining trap (F) and push
trap downwards until clear.
Remove trap from boiler along with pipe
to condensate pump.
Gas valve:
Check that the gas cock is turned off.
Remove condensate pump.
1 Undo the union, within the inner casing,
securing the valve to the gas/air tube.
2 Remove the black rubber tube from the
gas valve (G).
3 Release the gas inlet union at the inlet.
4 Remove
the solenoid connections at the
side of the gas valve.
Transfer the inlet pipe assembly to the
new gas valve.
Check for gas tightness when the new gas
valve has been fitted.
After re-assembly check CO/CO
as described in the section "Setting the
air/gas ratio".
INSTALLATION & SERVICING INSTRUCTIONS
8 716 115 219c (03.2010)
levels
2