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

Page: 27 / 96

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INSTALLATION SECTION 3
WATER
CONNECTIONS
UNVENTED SYSTEMS, Hi-Flo 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. 15
The heater can be used on unvented hot water storage systems, with the addition of an
Unvented Systems Kit, part number B172 available from Andrews Water Heaters.
See Parts List Page 51. The Wall Mounting Assembly is available as an optional extra.
Item C4 must be fitted into the temperature relief port in the water heater tank.
When assembling items C1 and C2, 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 C1
(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.
Fig 15.
C3