andrews RSC 150 Installation And Operation Manual page 14

INSTALLATION
When used in an unvented system, the Andrews storage water heater will supply hot
water at a pressure of 3.5 bar (50.8 psi) providing this pressure is available at the mains
feed. During conditions of no flow, whilst the burner is operating, the pressure of the
system will rise to a maximum of 6 bar (87.0 psi).
When testing the system it is recommended that a maximum test pressure of 8.62 bar
(125 psi) be employed.
The Andrews range of storage water heaters can be used on unvented hot storage water
systems with the addition, to the standard heater, of an "Unvented Systems Kit" Part No.
B213 obtainable 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 the requirement
G3 of the Building Regulations.
Fig.4 p11 lists and illustrates the component parts of the Unvented Systems Kit.
Fig.5 p12 illustrates the general arrangement of the components. The Wall Mounting Kit
is available as an optional extra.
Item F4 must be fitted into the Temperature Relief port (see Fig. 6, p13)
When assembling items F1 and F2 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
F1(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 F1.
The discharge pipe from the tundish should be of suitable metal and be at least one pipe
size larger than the outlet pipe on the safety devices.
(See Building Regulations Approved Document G3).
SECTION 3
WATER
CONNECTIONS
UNVENTED
SYSTEMS
11