Worcester Highflow 400 RSF Installation And Servicing Instructions page 43

Reassemble the manifold in the reverse order using new "O"
rings to replace any "O" rings which have been disturbed. Use
new sealing washers where appropriate.
Ensure that all clips and screws are correctly refitted.
Open the valves, fill and repressurise the system as described in
Section 12.2. Reassemble the appliance in the reverse order.
24. Water to Water Heat Exchanger Bottom Manifold.
Refer to Section 15.3-22 Water to Water Heat Exchanger.
Follow this procedure and replace the bottom manifold after the
bottom manifold/ water to water heat exchanger assembly has
been removed from the appliance. Retain the original water to
water heat exchanger and fit the new manifold using new "O"
rings.
Reassemble the appliance as described in Section 15.3-22.
25. Expansion Vessel. See Figs. 16 and 50.
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel, place the facia and control box
in the Service Position and lower the expansion vessel into the
Service Position, as described in Section 14.2 a, b and c.
Drain the heating circuit as described in Section 15.2 a.
Unscrew the union fitting on the right hand side of the expansion
vessel and remove the sealing washer. Ease the expansion vessel
assembly upwards to clear the support bracket and remove from
the appliance. Take care when removing as a small quantity of
water remains inside the vessel. Follow the procedure as
described in 15.2. Discard the expansion vessel.
Fit a replacement expansion vessel into the support bracket and
reconnect the union fitting using a new sealing washer.
Open the valves, fill and repressurise the system as described in
Section 12.2.
Reassemble the appliance in the reverse order.
26. Expansion Vessel Flexible Hose. See Figs. 16 and 50.
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel, place the facia and control box
in the Service Position and lower the expansion vessel into the
Service Position, as described in Section 14.2 a, b and c.
Drain the heating circuit as described in Section 15.2 a.
Unscrew the union fitting from behind the pump.
Remove and discard of the sealing washer. Ease the expansion
vessel assembly upwards to clear the support bracket and
remove from the appliance. Take care when removing as a small
quantity of water remains inside the vessel. Follow the procedure
as described in Section 15.2.
Unscrew the union fitting on the right hand side of the expansion
vessel. Remove and discard of the sealing washer.
Reconnect the hose in the reverse order using new sealing
Fig. 50. Expansion vessel and flexible hose.
WARNING:
There will be a small
quantity of water
remaining in the
expansion vessel
Expansion Vessel
Flexible Hose
Expansion
Vessel
Ease Expansion
Vessel upwards to
clear support
bracket
Support
Bracket
Fibre Washer
Union Fitting
washers. Ensure the orientation of the hose fittings does not
cause twisting or crimping of the hose when the expansion
vessel is repositioned in the boiler.
Open the valves, fill and repressurise the system as described in
Section 12.2.
Reassemble the appliance in the reverse order.
27. Pressure Relief Valve. See Figs. 16 and 51.
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel, place the facia and control box
in the Service Position as described in Section 14.2 a, b and c.
Drain the heating circuit as described in Section 15.2 a.
Withdraw the securing clip from the top manifold and ease the
pressure relief valve assembly forwards until clear of the
appliance. Unscrew the manual air vent and disconnect the
overflow pipe. Discard the valve and "O" ring seal.
Re-connect the overflow pipe and manual air vent to the
replacement valve. Fit a new "O" ring seal to the valve.
Re-connect the assembly to the appliance and replace the
securing clip.
Open the valves, fill and re-pressurise the system as described in
Section 12.2. Reassemble the appliance in the reverse order.
28. Manual Air Vent. See Figs. 16 and 51.
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel, place the facia and control box
in the Service Position as described in Section 14.2 a, b and c.
Drain the heating circuit as described in Section 15.2 a.
Remove the Pressure Relief Valve as described in Section 15.3-27.
Unscrew the manual Air Vent and discard along with its washer.
Replace with a new Manual Air Vent and washer.
Re-connect in the reverse order using a new "O" ring seal.
Reassemble the appliance in the reverse order.
29. Pressure Gauge. See Fig. 16.
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel, place the facia and control box
in the Service Position and lower the expansion vessel into the
Service Position, as described in Section 14.2 a, b and c.
Drain the heating circuit as described in Section 15.2 a.
Unscrew the pressure gauge out of the heat bank. Fit the
replacement pressure gauge using suitable thread sealing
compound. Open the valves, fill and re-pressurise the system as
described in Section 12.2.
Reassemble the appliance in the reverse order.
Fig. 51. Pressure relief valve and manual
air vent.
ÒOÓ ring seal
Manual air vent
and fibre washer
Pressure relief
valve
43
Securing clip
Top
manifold
Disconnect the
overflow discharge
pipe