Supplied By www.heating spares.co Tel. 0161 620 6677
9
when the system is heated. It can accept up to 8
litres (25kW) or 10 litres (29 & 35kW) of expan-
sion from within the system, generally this is
sufficient, however if the system has an unusu-
ally high water content, it may be necessary to
provide additional expansion capacity (see 6.19).
3A.6.6 FILLING POINT
A suitable method for initial filling of the system
and replacing water lost during servicing etc. is
required (see fig. 5). You should ensure this
method of filling complies with the local water
authority regulations.
3A.6.7 LOW PRESSURE SEALED SYSTEM
An alternative method of filling the system would
be from an independent make-up vessel or tank
mounted in a position at least 1 metre above the
highest point in the system and at least 5 metres
above the boiler (see fig. 5A).
The cold feed from the make-up vessel or tank
must be fitted with an approved non-return valve
and stopcock for isolation purposes. The feed
pipe should be connected to the return pipe as
close to the boiler as possible.
3A.6.8 FREQUENT FILLING
Frequent filling or venting of the system may be
indicative of a leak. Care should be taken during
the installation of the appliance to ensure all
aspects of the system are capable of withstand-
ing pressures up to at least 3 bar.
3A.7
ELECTRICAL SUPPLY
The appliance is supplied for operation on 230V
@ 50Hz electrical supply; it must be protected
with a 3-amp fuse. The method of connection to
the mains electricity supply must allow for com-
plete isolation from the supply. The preferred
method is by using a double-pole switch with a
contact separation of at least 3mm. The switch
must only supply the appliance and its corre-
sponding controls, i.e. time clock, room thermo-
stat, etc.
3A.8
SHOWERS
If the appliance is intended for use with a shower,
the shower must be thermostatically controlled
and be suitable for use with a combination boiler.
3A.9
MOUNTING ON A COMBUSTIBLE
SURFACE
If the appliance is to be fitted on a wall of
combustible material, a sheet of fireproof mate-
rial must protect the wall.
3A.10 TIMBER FRAMED BUILDINGS
If the appliance is to be fitted in a timber framed
building, it should be fitted in accordance with I.S.
813 and local Building Regulations.
The Institute of Gas Engineers publication (IGE/
UP/7) ‘Guide for Gas Installations in Timber
Frame Buildings’ gives specific advice on this
type of installation.
3A.11 INHIBITORS
Vokera recommend that an inhibitor - suitable for
use with copper and aluminium heat exchangers
- is used to protect the boiler and system from the
effects of corrosion and/or electrolytic action.
The inhibitor must be administered in strict ac-
cordance with the manufacturers’ instructions*.
*Water treatment of the complete heating system
- including the boiler - should be carried out in
accordance with I.S. 813 and the Domestic Wa-
ter Treatment Association’s (DWTA) code of
practice.
3A.12 DECLARATION OF CONFORMITY
A Declaration of Conformity (as defined in I.S.
813) must be provided on completion of the in-
stallation.
A copy of the declaration must be given to the
responsible person and also to the gas supplier if
required.