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1.3 SYSTEM DETAILS
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 6700. 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 sufficient for a small
1 bathroom dwelling (depending upon the flow 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 PulsaCoil 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 final 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
fitting appropriate flow 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 flow regulators are provided in Appendix A.
Note: If manifolds (available as an optional extra) are being used suitable flow
regulators are automatically provided in the manifold and do not need to be
provided at each outlet. See Appendix B for further details.
All the recommendations with regard to pipework systems in this manual are generally
based on the use of BS/EN Standard copper pipework and fittings.
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 fit connections when using the
optional flexible hose kits - see 2.2 Installation, Pipework connections.
It is also essential that if an alternative pipework material/system is chosen the
manufacturer confirms that the design criteria of the new system is at least equivalent
to the use of BS/EN Standard copper pipework and fittings.
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
flow/pressure outlets please discuss with the Gledhill technical department.
1.0 DESIGN
The hot water supply to a shower-mixing
valve should be fed wherever practical
directly from the PulsaCoil A-CLASS or be the
first 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 fitted
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 flushing 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.
