andrews 24/39, Installation Manual, Operation And Service Manual

Page: 22 / 96

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INSTALLATION SECTION 3
UNVENTED SYSTEMS, STANDARD RANGE
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.
Fig. 8
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. See Parts
List Page 51. The Wall Mounting Kit is available as an optional extra.
Item D4 must be fitted into the temperature relief port in the water heater tank.
D6 Adaptor - For use with D4 on heater models 40/61 63/62 & 84/87.
When assembling items D1 and D2, 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
fitted to the pipework, upstream of item D1.
The pipework fitted to the tundish outlet should be at least 28mm diameter and should be
terminated at a suitable drain (see Building Regulations 1991 Approved Document G3).
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 Building Regulations 1991.
Typical water service layout for Standard Range single heater unvented system is
shown in Fig 9.
Typical water service layout for Standard Range multiple heater unvented system is
shown in Fig 10.
WATER
CONNECTIONS
Fig 8.