ANDREWS COMBIfl o
24
GB
4.7 UNVENTED DESIGN
WARNING
Unvented Systems should only be fi tted by an Approved Installer
When using the Heater on an unvented hot water storage system, the Unvented System Kit, part number B328,
available from the manufacturer
must
be fi tted. See section 4.4. When used in an unvented system, the Heater
will supply hot water at a maximum of 3.5 bar or at the pressure available at the mains feed if this is lower. Dur-
ing conditions of no-fl ow, system pressure may rise to a maximum of 6 bar, whilst the burner is operating. When
testing the system, it is recommended that a maximum test pressure
of 7 bar
is used.
For the hot water supply
, a 25 litre expansion vessel is suitable for the stored volume of all models of the
Heater and an average pipework system. For systems with larger pipe volumes or additional storage, expan-
sion vessels with greater capacity are available. Assemble the components of the unvented system kit as shown
below
For the Central Heating supply
the expansion vessel must comply with BS4814 and must be sized on the basis
of total system volume and initial charge pressure. Initial minimum charge should not be less than 0.5 bar and
just take into account static head and specifi cation of any pressurising equipment.
When assembling the Pressure Reducing Valve and Double Non-Return Valve, ensure that the
fl ow arrows marked on the
components are pointing in the direction of fl ow, that is towards the
appliance.
The relief valves fi tted to this appliance must not be used for any other purpose. No fi tting should be installed
between the expansion valve and the cylinder. The cold water for services may be drawn from the 22mm com-
pression port up stream of the Pressure Reducing Valve. The water pressure at this point will be similar to that
available at the hot water outlet of the water heater. If higher fl ow rates are required for the cold water services, a
suitable tee fi tting should be fi tted to the pipework, upstream of the Pressure Reducing Valve.
The pipework fi tted to the tundish outlet should be at least 28mm diameter, made of metal and should be termi-
nated at a suitable drain (see Building Regulations Approved Document G3). All fi ttings and materials supplying
water to the storage vessel must be suitable for use with drinking water and listed in the current Water Research
Centre “Materials and Fittings Directory”. Installation of unvented hot storage water systems must comply with
Part G of Schedule 1 of the Building Regulations.
Expansion
Vessel
Wall Bracket
Assembly
Hose Assembly
Cold Water Inlet of Water
Cold Water Feed
Tundish
Check Valve
Expansion Valve
Pressure Reducing
Valve/Strainer
Balanced Cold Water
Take-off (if required)
Hot
Water
Temperature &
Pressure
Relief Valve
Содержание COMBIflo 100/300
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Страница 13: ...ANDREWS COMBIflo 11 GB Single Heating Circuit Immersion DHW Circulation pump ...
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