8
220683B
3.4 Water System
For an open vented system the boiler must be supplied
from an unrestricted water supply taken from a feed and
expansion cistern fitted at a maximum height of
27metres above the boiler.
The cold feed must be 15mm minimum size.
It is important that the relative positions of the pump,
cold feed and open vent are as shown in diagram 3.2.
The unrestricted open vent from the boiler must rise
continuously to discharge over the feed and expansion
cistern.
3.5 Domestic Hot Water System
General. The domestic hot water service must be in
accordance with the current issue of BS5546, refer also
to the current issue of BS6700.
3.6 Cylinder
For all systems supplying domestic hot water the
cylinder must be indirect. It is recommended that the
cylinder be fitted with some form of temperature control.
3.7 Fully Pumped Domestic Hot Water
The connection for this type of system MUST be as
shown in diagram 3.2 and 3.3.
3 W a t e r S y s t e m s
Diagram 3.2
0089M
FEED AND
EXPANSION
CISTERN
22mm VENT
(MIN.)
15mm (MINIMUM)
COLD FEED
OPEN VENTED FULLY PUMPED WATER SYSTEM
RECOMMENDED RELATIONSHIP BETWEEN
PUMP COLD FEED AND VENT
450mm
MIN.
HEIGHT
1150mm
MIN.
RETURN
FLOW
CYLINDER
PUMP
HEATING
150mm
MAX.
There must always
be a cold water path
to the return
connection
of the boiler.
BOILER
22mm (MINIMUM)
BY-PASS WITH
LOCKSHIELD VALVE
FLOW
RET.
