Sizing of copper discharge pipe ‘D2’
for common temperature relief valve outlet sizes
Valve
Minimum size
Minimum size
Maximum resistance
Resistance
outlet
of discharge
of discharge
allowed, expressed
created by
size
pipe D1
pipe D2 from
as a length of straight
each elbow
(mm)
tundish
pipe (i.e. no elbows
or bend
(mm)
or bends)
(metres)
(metres)
22
up to 9
0.8
G ½
15
28
up to 18
1.0
35
up to 27
1.4
28
up to 9
1.0
G ¾
22
35
up to 18
1.4
42
up to 27
1.7
35
up to 9
1.4
G 1
28
42
up to 18
1.7
54
up to 27
2.3
Positioning
The Zip Varipoint should be installed vertically with the electrical cover panel and
water connections underneath.
The unit is designed to be wall mounted using the wall fixings supplied with the
product. Ensure that the wall where the unit is to be located is sufficiently strong
to support the full weight of the unit (see dimensions) and capable of accepting
suitable fixings.
Position the Zip Varipoint to allow for provision of the cold water supply,
discharge fittings and pipework as well as access for future maintenance, repair
of the unit or its replacement.
N.B. Reasonable clearance will be required to give access to pressure
controls, element assembly, draining facility, pipe connections and
expansion vessel.
A minimum distance of 250mm should be allowed between the locating
bracket and the ceiling. A gap of 400mm should be left between the bottom of
the unit and any floor or work surface.
Do not install in a location where the unit or connecting pipework can freeze.
Zip Varipoint III Installation, Maintenance and User Instructions - August 2008
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