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If installed less than 2m above a pavement or platform to
which people have access (including balconies or flat roofs)
the 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 (i20-i30) and 6 litres (i25) 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.
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3A.7 ELECTRICAL SUPPLY
The appliance is supplied for operation on 230V @ 50Hz electri-
cal 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 fuse spur 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 mate-
rial, there is no requirement for a sheet of fireproof material to
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
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 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 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.
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