VOKERA Hydra Installation & Servicing Instructions Manual - page 8
6
Fig. 5
Make-up vessel
or tank
Automatic
air-vent
Non-return
valve
Stopcock
5.0 metres minimum
Heating
return
3.5
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.
3.6
WATER CIRCULATION
Detailed recommendations are given in BS 5449
Part 1 and BS 6798. The following notes are for
general guidance only.
3.6.1
PIPEWORK
It is recommended that copper tubing to BS 2871 Part
1 is 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 atten-
tion should be paid to pipes passing through
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 ex-
ternal 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 10 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.
3.6.6
FILLING POINT
A method for initial filling of the system and
replacing water lost during servicing etc. is
provided on the appliance. This method complies
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 (fig. 5). The cold feed from the
make-up vessel or tank must be fitted with an
approved non-return valve and stopcock for iso-
lation purposes. The feed pipe should be con-
nected 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 withstand-
ing 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 mm. The switch
must only supply the appliance and its
corresponding controls, i.e. time clock, room ther-
mostat, etc. Alternatively an un-switched shuttered
socket with a fused 3-pin plug both complying
with BS 1363 is acceptable.
3.8
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.
3.9
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.
3.10
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 a Timber Frame
Buildings”.