Supplied By www.heating spares.co Tel. 0161 620 6677
SIZING OF ADDITIONAL EXPANSION VESSELS: TABLE 3
Deduct from the value given in the table the 7 litre vessel supplied.
Note: This pressure can be increased up to 1.5 bar to suit static head situations, see item 10, other appliance instructions in the
SERVICING INSTRUCTIONS
It is most important that the correct concen-
tration of the water treatment product is
maintained in accordance with the manu-
facturers’ instructions.
If the boiler is installed in an existing system
any unsuitable additives MUST be removed
by thorough cleansing.
BS 7593:1992 details the steps necessary
to clean domestic central heating system.
Also check pipework and renew any corrod-
ed pipework or fittings. Valve glands must
be repacked or replaced wherever neces-
sary and any defective controls exchanged.
B) Where fitting a make up vessel would be
difficult re - pressurisation of the system can
be done. See section on FILLING.
If the capacity of the central heating system
should exceed 85 litres, an additional ves-
sel should be installed on the return to the
combination boiler from the heating system
(Fig. 7). Guidance on vessel sizing is given
in (Table 3).
Reference should be made to British Gas
Publications
<<Material and Installation
Specifications for Domestic Central Heating
and Hot Water >>. Draining taps should be at
least 1/2" in BSP nominal size and be in
accordance with BS 2879.
4.8.9
Installation to an existing central heating
system
The combination boiler is designed to oper-
ate on a sealed system only. Therefore if
the existing system is of the open water
type it will have to be modified to comply
with BS 5376 Part 2.
Before, installing a new combination boiler to
an existing system, flush out the old system
with a recommended descaling agent.
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