Worcester benchmark ZWB 7-25 R 25 HE Design, Installation And Servicing Instructions page 55

General notes
Thermostatic radiator valves
It is recommended that this type of valve is fitted to all the radiators
except one, usually a radiator where the room thermostat is fitted.
They should conform to the requirements of BS2767:10.
Showers, bidets, taps and mixing valves – R 25 & 30
Boilers
Standard hot and cold taps and mixing valves must be suitable for
operating at mains pressure. Thermostatically controlled or pres-
sure equalising shower valves will guard against the flow of water
at too high a temperature.
Hot and cold mains fed water can be supplied directly to an over-
rim flushing bidet subject to local water company requirements.
With all mains fed systems the flow of water from individual taps
will vary with the number of outlets operated simultaneously and
the cold water mains supply pressure to the property.
Flow balancing using "ball-o-fix" type valves is recommended to
avoid an excessive reduction in flow to individual outlets.
For further information contact Worcester Heat Systems Ltd.
Technical Services Department.
Hot and cold flow – R 25 & 30 Boilers
The flow of water demanded from both hot and cold service out-
lets is dependent upon the mains supply. It may not be possible in
some installations to operate all outlets simultaneously.
Water mains failure – R 25 & 30 Boilers
If there is a failure of the mains water supply then no water will be
available at a tap or shower until the mains supply is restored. The
appliance will still operate in the central heating mode.
Use in hard water areas – R 25 & 30 Boilers
In exceptionally hard water areas a device to prevent scale forma-
tion may be fitted. Installation of a scale inhibitor assembly should
be in accordance with the requirements of the local water com-
pany. An isolating valve should be fitted to allow for servicing.
6 720 610 577 GB (03.11)
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