Pressure Relief Valve; Bypass Valve; Expansion Vessel - Worcester 41-311-67 Installation, Commissioning And Servicing Instructions

SERVICE AND SPARES
6.8.23 CH PRESSURE RELIEF VALVE
B Remove the hydraulic block from the boiler (See
Removing the Hydraulic Block).
1. Release the spring clip from the Pressure Relief Valve
housing.
2. Withdraw the Pressure Release Valve from its
housing.
2.
Fig. 117 PRV removal
B To refit, follow the above in reverse. Ensure any seals
that have been disturbed are renewed.

6.8.24 BYPASS VALVE

1. Remove the two spring clips at either end of the
copper bypass pipe.
1.
Fig. 118 Removing the bypass valve
B Undo the screw securing the left hand plastic housing
to the heat exchanger.
B Move the housing to the left to free up the one end of
the pipe.
B Remove the pipe from the right hand housing to reveal
the bypass valve.
2. Using a pair of pliers, pull out the bypass valve from
the housing
B To refit, follow the above in reverse. Ensure any seals
renewed.
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1.
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2.
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6.8.25 EXPANSION VESSEL

The expansion vessel can be replaced with the boiler in
position if there is a side exit flue fitted and a minimum
clearance of 340mm above the boiler casing. If a vertical
flue is fitted then a similar clearance to one side of the
flue is required.
If this clearance is not available, then the boiler will need
to be removed from the mounting frame to gain access
to the expansion vessel.
Alternatively a second vessel of at least the capacity of
seven litres can be fitted to the return from the heating
system as close as possible to the boiler.
Expansion vessel replacement (Boiler in place)
B Isolate mains power from the boiler.
B Lower the control panel to the service position.
B Isolate the boiler from the heating system (and
cylinder return if internal diverter valve is fitted) using
service valves.
B Drain the boiler.
B At the pump manifold, release the clip and disconnect
the expansion vessel hose.
1.
Fig. 119 Removing the expansion vessel
1. Remove screw (1) retaining the vessel to the top of
the boiler casing.
2. Pull the vessel up (2) and out over the flue system or
to one side if fitted with a vertical flue.
B Remove the flexible hose from the expansion vessel
and fit to the replacement vessel using a new seal.
B Reassemble expansion vessel into wall frame and
reconnect the flexible pipe to pump manifold and
secure with the clip.
6 720 644 743a (2010/10)
2.