Table of Contents
Advertisement
3.6.2
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'.
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.
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 8
(28HE) or 10 (32 & 36HE) 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 6.19).
3.6.6
FILLING POINT
A method for initial filling of the system and
replacing water lost during servicing etc. directly
from the mains supply, is provided (see fig. ). This
method of filling complies with the current Water
Supply (Water Fittings) Regulations 1999 and Water
Bylaws 2000 (Scotland). If an alternative location
is preferred, it should be connected as detailed in
fig.5.
control
valve
flow/return
pipe
fig.5
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.
The drain
control
temporary
valve
connection
double
check valve
supply
pipe
Make-up vessel
or tank
Automatic
air-vent
Non-return
valve
fig.5A
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
category)
. The switch must only supply the
appliance 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
combustible 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
accordance 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.
3.11
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.
Stopcock
Heating
return
,5mm (3° high-voltage
7
Advertisement
Table of Contents
