11
Heating
circuit
return
Double check
valve assembly
Hose
unions
Temporary
Hose
Test
valve
Stop
valve
Mains
water
supply
fig. 6
GW 400/1
3.7.2 Filling and make up
The system should be filled with water
via a separate filling point fitted at a
convenient position on the heating
circuit. Where local Water Authority
Regulation allows, a temporary
connection to the mains may be used
(fig. 6). The connection must be
removed when filling is completed.
Where local Water Authority
Regulation does not allow temporary
connection, a sealed system filler
pump with break tank must be used.
The heating system will not be filled
automatically from the domestic hot
water side.
(Alternative methods of filling sealed
systems are given in BS 5449).
3.7.3 Pressure relief valve
A pressure relief valve is provided
ready assembled within the boiler
(5, fig. 7). This safety device is
required on all sealed C.H. systems
and is pre-set at 3 bar and provided
with a 3/4 in. BSP connection for a
discharge pipe, which must be of no
less than 15 mm diameter.
3.7.4 Pressure and temperature gauge
This is factory fitted to the boiler and
indicates the primary circuit pressure
to facilitate filling and testing, as well
as showing the temperature of the
central heating system water.
11
8
1
4
10
7
9
5
6
2
3
fig. 7
GW 609/1
