3.10 Guide to system requirements
3.10.1
Water circulation system
Detailed recommendations for the water circulation sys-
tem are given in BS 6798 and BS 5449: Part 1 (for small
bore and micro bore central heating systems). Pipework
not forming part of the useful heating surface should be
insulated to help prevent heat loss and possible freezing,
particularly where pipes are run through roof spaces
and ventilated underfloor spaces. Draining taps must be
located in accessible positions which permit the draining
of the whole system including the boiler and the hot
water system. Draining taps should be at least 1/2 in.
BSP nominal size and be in accordance with BS 2879.
The boiler is suitable for use with minibore or microbore
systems. Copper tubing to BS 2871: Part 1 should be used
for water carrying pipework. All capillary joints in all
DHW pipework must be made with lead free solder.
Particularly where a new boiler is to be fitted to an exist-
ing system, it is good practice that the system is thor-
oughly cleansed.
Caution!
To prevent the formation of deposits and pre-
vent serious damage to the appliance and sys-
tem, cleansers must be used carefully and must
be completely removed by thoroughly flushing
the system. Cleansers should only be left in
systems for a maximum of 24 hours.
This cleansing must take place prior to the fitting of the
new boiler and be in accordance with BS 7593. For
advice on the application of system cleansers contact
Sentinel, Betz Dearborn Ltd. Widnes, Cheshire, WA8
8UD. Tel: 0151 420 9595, or Fernox, Alpha Fry
Technologies, Tandem House, Marlow Way, Croydon, CR0
4XS. Tel 0870 8700362.
3.10.2 Filling and preparing heating system
The system can be filled using the built in filling loop
(ecoTEC plus combination boilers only) or via a separate
filling point fitted at a convenient position on the heat-
ing circuit. 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 domes-
tic hot water side. (Alternative methods of filling sealed
systems are given in BS 5449).
3.10.3 Pressure relief valve
A pressure relief valve is provided with the boiler. This
safety device is required on all sealed C.H. systems and
is preset at 3 bar and provided with a 15 mm compres-
sion connection for a discharge pipe, which must be of
no less than 15 mm in diameter. The pressure relief
valve must not be used for draining purposes.