gledhill BoilerMate CP 120 Design, Installation & Servicing Instructions page 10

DESIGN
Hot and Cold Water System
Pipe Sizing / Materials
To achieve even distribution of the available supply of hot and cold water, it is
important in any mains pressure system, that the piping in a dwelling should be sized
in accordance with BS EN 806:1-5: BS EN 8558:2011. This is particularly important in
a large property with more than one bathroom.
However, the following rule of thumb guide lines should be adequate for most smaller
property types as long as water pressures are within the recommended range.
1. A 15mm copper or equivalent external service may be suffi cient for a small 1
bathroom dwelling (depending upon the fl ow rate available), but the minimum
recommended size for new dwellings is 22mm (25mm MDPE).
2. The internal cold feed from the main incoming stop tap to the BoilerMate CP should
be run in 22mm pipe. The cold main and hot draw-off should also be run in 22mm
as far as the branch to the bath tap.
3. The fi nal branches to the hand basins and sinks should be in 10mm and to the
baths and showers in 15mm (1 metre minimum).
4. We would recommend that best results for a balanced system are achieved
by fi tting appropriate fl ow regulators to each hot and cold outlet. This is
particularly relevant where the water pressures are above the recommended
water pressure range. Details of suitable fl ow regulators are provided in
Appendix A.
All the recommendations with regard to pipework systems in this manual are generally
based on the use of BS/EN Standard copper pipework and fi ttings.
However, we are happy that plastic pipework systems can be used in place of copper
internally as long as the chosen system is recommended for use on domestic hot
and cold water systems by the manufacturer and is installed fully in accordance with
their recommendations.
This is particularly important in relation to use of push fi t connections when using the
optional fl exible hose kits - see installation section of this manual.
It is also essential that if an alternative pipework material/system is chosen the
manufacturer confi rms that the design criteria of the new system is at least equivalent
to the use of BS/EN Standard copper pipework and fi ttings.
Taps/Shower Fittings
Aerated taps are recommended to prevent splashing.
Any type of shower mixing valve can be used as long as both the hot and cold
supplies are mains fed. However all mains pressure systems are subject to
dynamic changes particularly when other hot and cold taps/showers are opened
and closed, which will cause changes in the water temperature at mixed water
outlets such as showers. For this reason and because these are now no more
expensive than a manual shower we strongly recommend the use of thermostatic
showers with this appliance.
The shower head provided must also be suitable for mains pressure supplies.
However, if it is proposed to use a 'whole body' or similar shower with a number of
high fl ow/pressure outlets please discuss with the Gledhill technical department.
The hot water supply to a shower-mixing valve should be fed wherever practical
directly from the BoilerMate CP or be the fi rst draw-off point on the hot circuit. The
cold supply to a shower-mixing valve should wherever practical be fed directly from
the rising mains via an independent branch. The shower must incorporate or be
TECHNICAL DATA
fi tted with the necessary check valves to provide
back-syphonage protection in accordance with
the Water Regulations.
The supply of hot and cold mains water directly
to a bidet is permitted provided that it is of the
over-rim fl ushing type and that a type 'A' air gap
is incorporated.
Hot and Cold Water System
If the length of the hot water draw off pipework
is excessive and the delivery time will be more
than 60 seconds before hot water is available at
the tap, you may wish to consider using trace
heating to the hot water pipework such as the
Raychem HWAT system. Please consult Gledhill
Technical Department for further details.
Note: A conventional pumped secondary
circulation system is NOT suitable for use with
this appliance.
It is important that the cold water pipework
is adequately separated/protected from any
heating/hot water pipework to ensure that
the water remains cold and of drinking water
quality.
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