INSTALLATION
SECTION 3
Unvented Systems should be fitted by an Approved Installer.
When used in an unvented system, the Andrews Water Heater will supply hot water at
a pressure of 3.5bar (50.8lbf/in
2
) provided that this pressure is available at the mains
feed. During conditions of no-flow, system pressure may rise to a maximum of 6bar
(87lbf/in
2
) whilst the burner is operating. When testing the system, it is recommended
that a maximum test pressure of 8.62bar (125lbf/in
2
) is employed.
The heater can be used on unvented hot water storage systems, with the addition of
an Unvented Systems Kit, part number B171 available from Andrews Water Heaters.
All fittings and materials must be suitable for use with drinking water and listed in the
current Water Research Centre "Materials and Fittings Directory".
Installation of unvented hot storage water systems must comply with Part G of
Schedule 1 of the Current Building Regulations.
Fig.4 p12 lists and illustrates the component parts of the Unvented Systems Kit.
Fig.5 p13 illustrates the general arrangement of the components.
The Wall Mounting Kit is available as an optional extra.
Items D4/D6 must be fitted into the Temperature Relief port (see Fig.6, p13).
When assembling items D1 and D2 care must be taken to ensure that the flow arrows
marked on the components are pointing in the direction of flow i.e. towards the water
heater.
The cold water for services may be drawn from the 22mm compression port on item
D1(a). The water pressure at this point will be similar to that available at the hot water
outlet of the water heater. If port (a) is not used it should be sealed with the blanking
plug supplied.
If higher flow rates are required for the cold water services a suitable “tee” fitting
should be included in the pipework upstream of item D1.
The pipework fitted to both tundish outlets should be at least 28mm diameter and
should be terminated at a suitable drain (see Current Building Regulations Approved
Document G3).
11
WATER
CONNECTIONS -
UNVENTED
SYSTEMS
