Publication No. 5105703
12 Installation Requirements
Circulation Pump Selection
The resistance through the heat exchanger
when operating with a water flow rate
producing an 11°C temperature rise at
maximum boiler output are shown in the
table. If other controls such as three position
valves are used in the system, the resistance
through them, quoted in their manufacturers
literature must be taken into account. The
pump may be fitted on either the flow or
return and MUST be wired directly to the
boiler terminal block. It must be fitted with
two isolating valves which are positioned as
close to the pump as possible. Closing of
any valve must always leave the open vent
unobstructed.
PRF0011A
Cylinder
Optional
Zone Valve
By-pass using bathroom
radiator connected into
Gravity Circuit and fitted
with two lockshield valves
to be installed when a
zone valve is fitted in
Gravity Circuit
Min.
Circulating
Head 1.2m
(4ft)
PRF0007A
1
.076
Imp. Gall/min.
Litres/sec
1.5
6
3.0
12
4.5
18
6.0
24
7.5
30
9.0
36
10.5
42
kN/m² in wg
2
.152
3
.227
4
.303
5
.379
6
.455
7
.53
Without
Injector
Disc
With
Injector
Disc
Model
Water Flow Rate
Boiler Resistance
with Disc
Without Disc
Litres/sec
gal/min
KN/m² in wg
KN/m² in wg
40
.25
3.34
2.7
11.0
.75
3.0
50
.32
4.17
4.0
16.0
1.25
5.0
60
.38
5.0
5.7
23.0
1.75
7.0
80
.51
6.67
10.5
42.0
3.0
12.0
Fig. 8
