AIC COILMASTER 100, Installation And Maintenance Manual For The Installer And The User

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G-084383_EN • 03
P
roduct
I
nstallatIon
Discharge pipe from safety valves
The Building Regulation G3 requires that any dis-
charge from an unvented system is conveyed to
where it is visible, but will not cause danger to per-
sons in or about the building.
The tundish and discharge pipes should be fi tted
in accordance with the requirements and guidance
notes of Building Regulation G3. The G3 Require-
ments and Guidance sections 3.50 - 3.63 are de-
tailed below.
For discharge pipe arrangements not covered by
G3 Guidance advice should be sought from your
local Building Control Offi cer.
Main characteristics :
î
Any discharge pipe connected to the pressure
relief devices (Expansion Valve and Tempera-
ture/Pressure Relief Valve) must be installed in a
continuously downward direction and in a frost-
free environment.
î
Water may drip from the discharge pipe of the
pressure relief device.
î
This pipe must be left open to the atmosphere.
î
The pressure relief device is to be operated regu-
larly to remove lime deposits and to verify that it is
not blocked.
î
A typical discharge pipe arrangement is shown
on next page.
î
Discharge pipe-work D2 can now be
a plastic pipe but only pipes that have
been tested to a minimum 110°C
must be used.
î
Discharge pipe D2 can now be plumbed
into the soil stack but only soil stacks
that can handle temperatures of 99°C
or greater should be used.
Extract from “The Building Regulation G3” :
Discharge pipe D1
3.50 Safety devices such as temperature relief
valves or combined temperature and pressure and
pressure relief valves should discharge either di-
rectly or by way of a manifold via a short length of
metal pipe (D1) to a tundish.
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3.51 The diameter of discharge pipe (D1) should
be not less than the nominal outlet size of the tem-
perature relief valve.
3.52 Where a manifold is used it should be sized
to accept and discharge the total discharge from
the discharge pipes connected to it.
3.53 Where valves other than the temperature
and pressure relief valve from a single unvented hot
water system discharge by way of the same mani-
fold that is used by the safety devices, the manifold
should be factory fi tted as part of the hot water stor-
age system unit or package.
Tundish
3.54 The tundish should be vertical, located in
the same space as the unvented hot water storage
system and be fi tted as close as possible to, and
lower than, the valve, with no more than 600mm of
pipe between the valve outlet and the tundish.
To comply with the Water Supply (Water
Fittings) Regulations, the tundish should
incorporate a suitable air gap.
3.55 Any discharge should be visible at the
tundish. In addition, where discharges from safety
devices may not be apparent, e.g. in dwellings oc-
cupied by people with impaired vision or mobility,
consideration should be given to the installation of
a suitable safety device to warn when discharge
takes place, e.g. electronically operated.
Discharge pipe D2
3.56 The discharge pipe (D2) from the tundish should:
a. have a vertical section of pipe at least
300mm long below the tundish before
any elbows or bends in the pipework; and
b. be installed with a continuous fall
thereafter of at least 1 in 200.
3.57 The discharge pipe (D2) should be made of:
a. metal; or
b. other material that has been demon-
strated to be capable of safely with-
standing temperatures of the water dis-
charged and is clearly and permanently
marked to identify the product and per-
formance standard (e.g. as specifi ed in
the relevant part of BS 7291)
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G3 Requirements (UK only)
Requirements for the Hydraulic Circuits