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Stop cock & drain
Install a full bore stop cock or ball valve (not supplied) before the inlet group assembly on the
incoming mains water supply so the unit can be isolated when required. A full bore drain cock
(not supplied) must be fitted to the supply pipework, between the cylinder and the inlet group, at
as low a level as possible. An air break must be provided at the point of drainage. (see Figure 5a
/ 5b).
Distribution pipework
Pipework supplying the hot water taps must be capable of withstanding a maximum pressure of
7 bar at a temperature of 90°C and should be run in 22mm throughout the property. Only short
lengths (max 1 metre) of 15mm should be used to connect baths, showers and basin taps etc. If
using a secondary / pumped return circuit, all pipework must be well insulated. The circulator
(bronze pump) should be time and/or temperature controlled to reduce energy consumption.
Taps & fittings pressure rating
All taps and fittings incorporated into the unvented system should have a rated operating pressure
of 7 bar or above.
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