11
terminal must be protected by a guard of durable material. The
guard must be fitted centrally over the terminal. Refer to I.S. 813,
when the terminal is 0.5 metres (or less) below plastic guttering
or 1 metre (or less) below painted eaves.
3A.5 AIR SUPPLY
The following notes are intended for general guidance only.
This appliance is a room-sealed, fan-flued boiler, consequently
it does not require a permanent air vent for combustion air
supply.
When installed in a cupboard or compartment, ventilation for
cooling purposes is also not required.
3A.6 WATER CIRCULATION
Specific recommendations are given in I.S. 813. The following
notes are for general guidance only.
3A.6.1 PIPEWORK
It is recommended that copper tubing be used in conjunction
with soldered capillary joints.
Where possible pipes should have a gradient to ensure air is
carried naturally to air release points and that water flows
naturally to drain cocks.
Except where providing useful heat, pipes should be insulated
to avoid heat loss and in particular to avoid the possibility of
freezing. Particular attention should be paid to pipes passing
through ventilated areas such as under floors, loft space and
void areas.
3A.6.2 AUTOMATIC BY-PASS
The appliance has a built-in automatic by-pass, consequently
there is no requirement for an external by-pass, however the
design of the system should be such that it prevents boiler
‘cycling’.
3A.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.
3A.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.
3A.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 8 litres of expansion from within
the system, generally this is sufficient, however if the system
has an unusually high water content, it may be necessary to
provide additional expansion capacity (see 6.18).
3A.6.6 FILLING POINT
A method for initial filling of the system and replacing water lost
during servicing etc. is provided (see fig. 7). 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. 8). 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
withstanding 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 complete isolation from the supply. The preferred method
is by using a double-pole switch with a contact separation of at
least 3,5 mm (3° high-voltage category). The switch must only
supply the appliance and its corresponding controls, i.e. time
clock, room thermostat, etc.
3A.8 MOUNTING ON A COMBUSTIBLE
SURFACE
If the appliance is to be fitted on a wall of combustible material,
a sheet of fireproof material must protect the wall.
3A.9 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.10 INHIBITORS
Vokèra recommend that an inhibitor - suitable for use with
copper 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 accordance 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 Water Treatment Association’s (DWTA) code of
practice.
3A.11 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.12 DECLARATION OF CONFORMITY
A Declaration of Conformity (as defined in I.S. 813) must be
provided on completion of the installation.
A copy of the declaration must be given to the responsible
person and also to the gas supplier if required.
