6
Fig. 6
flow/return
pipe
control
valve
temporary
connection
control
valve
supply
pipe
double
check valve
Fig. 5
3.6.6
FILLING POINT
A method for initial filling of the system and replac-
ing water lost during servicing etc. is required (see
fig. 5). This method of filling must comply with the
current Water Supply (Water Fittings) Regulations
1999 and Water Bylaws 2000 (Scotland).
3.6.7
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.
3.6.8
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 withstanding
pressures up to at least 3 bar.
3.7
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 correspond-
ing controls, i.e. time clock, room thermostat, etc.
Alternatively an un-switched shuttered socket with
a fused 3-pin plug both complying with BS 1363
is acceptable.
Make-up vessel
or tank
Automatic
air-vent
Non-return
valve
Stopcock
5.0 metres minimum
Heating
return
Fig. 5A
3.8
MOUNTING ON A COMBUSTIBLE
SURFACE
If the appliance is to be fitted on a wall of com-
bustible material, a sheet of fireproof material must
protect the wall.
3.9
TIMBER FRAMED BUILDINGS
If the appliance is to be fitted in a timber framed
building, it should be fitted in accordance with the
Institute of Gas Engineers publication (IGE/UP/
7) ‘Guide for Gas Installations in Timber Frame
Buildings’.
3.10
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 accord-
ance with the manufacturers instructions*.
*Water treatment of the complete heating system
- including the boiler - should be carried out in
accordance with BS 7593 and the Domestic Water
Treatment Association’s (DWTA) code of practice.