Supplied By www.heating spares.co Tel. 0161 620 6677
7
Make-up vessel
or tank
Automatic
air-vent
Non-return
valve
Stopcock
5.0 metres minimum
Heating
return
ventilated areas such as under floors, loft space,
and void areas.
3.6.2
AUTOMATIC BY-PASS
The appliance has a built-in automatic by-pass,
consequently there is no requirement for an exter-
nal by-pass, however the design of the system
should be such that it prevents boiler ‘cycling’.
3.6.3
DRAIN COCKS
These must be located in accessible positions to
facilitate draining of the appliance and all water
pipes connected to the appliance. The drain cocks
must be manufactured in accordance with BS
2879.
3.6.4
AIR RELEASE POINTS
These must be positioned at the highest points in
the system where air is likely to be trapped. They
should be used to expel trapped air and allow
complete filling of the system.
3.6.5
EXPANSION VESSEL
The appliance has an integral expansion vessel to
accommodate the increased volume of water
when the system is heated. It can accept up to 6
litres (12-15-20HE), 8 (25HE) and 10 litres (30-
35HE) of expansion from within the system, gen-
erally this is sufficient, however if the system has
an unusually high water content, it may be neces-
sary to provide additional expansion capacity (see
6.19).
3.6.6
FILLING POINT
A method for initial filling of the system and re-
placing 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 (Scot-
land).
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 complete
isolation from the supply. The preferred method is
by using a double-pole switch with a contact
separation of at least 3,5mm (3° high-voltage
category). The switch must only supply the appli-
ance and its corresponding 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.
3.8
MOUNTING ON A COMBUSTIBLE SURFACE
If the appliance is to be fitted on a wall of combus-
tible 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 ac-
cordance 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 prac-
tice.
flow/return
pipe
control
valve
temporary
connection
control
valve
supply
pipe
double
check valve
Fig. 5
Fig. 5A
