Secondary Cir
c
uit
Installation
9
Cold water
storage cistern
Vent pipe
Insulating jacket
Overflow
warning pipe
If feeding a shower cold feed
to cylinder should always be
above cold water down service
pipe to prevent scolding
450mm
minimum offset
Boiler
primary
Solid fuel
primary
Solar
thermal
Breather with filter
Purpose made
fully fitted lid
Mains water
supply pipe
with isolating
stop valve
Ball valve with
backing plate
Isolating gate valves
close to cistern
Cold water down service pipe
Cold water feed to cylinder
Further isolating gate valves can
be fitted at a more convenient
location if required
To cold water outlet points
To hot water
outlet points
(Diagram of principals only)
Drain cock
4.4 DuoWave Plus 300
The Grant DuoWave Plus 300 Open
Vented Indirect Solar cylinder is
designed to be used as part of a static
Open Vented hot water system. It
should be installed in accordance with
BS6700:2006, The Building Regulations
Part L and also the relevant Water
Regulations – i.e. the Water Supply
(Water Fittings) Regulations 1999 or the
Water Byelaws 2000, Scotland.
Important: This open vented version
of the DuoWave Plus MUST be used if
an ‘uncontrolled’ heat source such as
a solid fuel or wood burning appliance
is to be connected to the cylinder,
along with a ‘conventional’ boiler and
Solar Thermal.
The maximum working head for the
Grant DuoWave Plus Solar cylinder is
30m. Ensure that this is suitable for
your installation before proceeding. If
you are in doubt about the suitability of
the cylinder for the system and
appliances concerned then please
contact the Grant Technical Helpline for
assistance.
Figure 4-1 shows the installation of the
DuoWave Plus 300 Indirect Solar
cylinder installed as part of an open
vented hot water system.
4.5 Cold Water Storage
Cistern (CWSC)
Cisterns should be installed in
accordance with BS6700:2006 and also
the relevant Water Regulations – i.e. the
Water Supply (Water Fittings) Regulations
1999 or the Water Byelaws 2000,
Scotland.
If the cistern is used to provide cold
water to the hot water supply only, it
should have a capacity at least equal to
the hot water cylinder it is supplying.
4.6 Cold Feed Pipe
The cold water feed pipe from the
CWSC to the cylinder should be sized
in accordance with BS6700:2006. This
feed pipe should not supply water to
any other fitting.
Connect the cold feed pipe to the cold
inlet connection of the cylinder. Refer to
Figure 2-3.
A service valve (quarter turn lever
operated full-bore valve) should be fitted
in the feed pipe in a convenient and
accessible position, e.g. adjacent to the
cylinder. If required a second service
and cold feed pipe should not be
connected together.
Under no circumstances should the
vent pipe from an open vented hot
water cylinder terminate over any
combined feed and expansion cistern
(F&EC) connected to a primary circuit or
any cistern used for the storage and
distribution of wholesome water.
An OSV pipe should be insulated to
protect it from freezing.
4.8 Primary Connections
The ‘uncontrolled’ heat source should
be connected to the middle coil via the
two 28mm compression connections.
The Solar Thermal primary should be
connected to the bottom coil via the
two 22mm compression connections,
with the Boiler primary connected to
the top coil 22mm compression
connections.
All primary pipework should be
insulated between boiler and cylinder.
valve can be fitted in the cold water feed
pipe located adjacent to the CWSC.
A Drain Cock (DC) must be fitted at the
lowest point of this supply pipe
adjacent to the cylinder to enable
draining of the pipe and cylinder.
4.7 Open Vent Pipe
The cylinder must be installed with an
Open Safety vent (OSV) pipe. This must
be connected to the hot water outlet on
the top of the cylinder and rise
continuously to terminate over the
CWSC. Refer to Figure 4-2.
There should be an ‘offset’ of at least
450mm in the OSV pipe to reduce the
tendency for thermal circulation and
loss of heat from the vent pipe. Refer to
Figure 4-1.
The OSV pipe must be of an adequate
diameter, the minimum pipe size being
22mm.
Important: The OSV pipe
MUST
be
permanently open with
NO
obstructions
(e.g. no valves fitted). The OSV pipe
H
V
Figure4-2:
Open vented cylinder
