Potterton Performa 28i Installation And Servicing Instructions page 13

Other Tap
Outlets
Check
Valve
Pressure
Reducer Valve
Stop Tap
Fig. 6
Boiler
Expansion
Vessel
To Hot
Taps
6.0 System Details
6.8 Domestic Hot Water Circuit (Fig. 6)
1. All DHW circuits, connections, fittings, etc.
should be fully in accordance with relevant
standards and water supply bye-laws.
2. Your attention is drawn to:
IRN 116 and the Water Supply (Water Fittings)
Regulations 1999 Schedule 2, Section 8,
paragraph 17. Sealed primary circuits and/or
secondary hot water systems shall incorporate a
means for accommodating the thermal expansion
of water to prevent any discharge from the circuit
and/or system, except in an emergency situation.
3. When the system includes any device which
prevents water expanding back towards the
supply (check valve, loose jumpered stopcock,
water meter, water treatment device), then an
expansion vessel must be fitted (e.g. Zilmet
160ml, R 1 / 15bar). To comply with Byelaw 91, a
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check valve must also be fitted on the supply as
shown, to ensure efficient operation and also to
prevent the reverse flow of hot water into the
supply pipe.
4. If the hot water expansion is not provided for,
then high pressures can develop which may
result in damage to fittings and devices on the
system.
5. The boiler's maximum working mains pressure
is 8 bar, therefore all pipework, connections,
fittings, etc. should be suitable for pressures in
excess of 10 bar. A pressure reducing valve must
be fitted for pressures in excess of 10 bar. The
manufacturer of any outlet fittings, such as a
shower valve, may require a lower maximum
pressure. The pressure reduction must take
account of all fittings connected to the DHW
system.
6.9 Showers
1. If a shower control is supplied from the
appliance it should be of the thermostatic or
pressure balanced type. Thermostatic type
shower valves provide the best comfort and
guard against water at too high a temperature.
Existing controls may not be suitable - refer to the
shower valve manufacturer.
6.10 Hard Water Areas
1. If the area of the installation is recognised as a
HARD WATER AREA then a suitable device
should be fitted to treat the mains water supply to
the boiler.
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