Supplied By www.heating spares.co Tel. 0161 620 6677
4 Heating System
4.1 General
The boiler is for use only with sealed central heating systems.
The safety valve is an integral part of the boiler and it cannot
be adjusted.
The digital read-out on the controls fascia indicates the
system pressure when there is no demand.
The circulation pump is integral with the boiler.
4.2 Expansion Vessel
The boiler has an integral expansion vessel with a capacity of
8 litres (1.76 gallons), with a change pressure of 0.5bar.
NOTE: The expansion vessel volume depends on the total
water system volume and the initial system design pressure.
To check if an additional expansion vessel is required, an
accurate calculation of vessel size is given in the current
issue of BS5449 and BS7074 Part 1, for IE refer to the current
edition of I.S.813 “Domestic Gas Installations”.
4.3 Flow Rate
The flow rate through the boiler must not be allowed to fall
below that given in diagram 1.2.
The system can be fitted with a lockable balancing valve if
necessary in the main flow or return pipes shown as valve “A”
in diagram 4.1.
Diagram 4.1
13043
BOILER
DRAIN
POINT
'A'
FLOW CONTROL
V
ALVE
HEATING
CIRCUIT
RETURN
ADDITIONAL
EXPANSION
VESSEL
(if required)
BYPASS
(if required)
Diagram 4.2
13102
automatic bypass - fully open
automatic bypass - factory setting
automatic bypass - fully closed
pump speed 2pump speed 1
Remaining Conveyancing Capacity (mH2O)
0
1
2
3
4
0.5
1.5
2.5
3.5
4.5
5
900700500300100-100
150013001
100
Litres/hr