Technical data

Installation
A Class HP Installation and User Instructions R02583-2 09/13 Page 13
5.1.4 Balanced cold water supply
If a balanced cold water supply is required
(recommended) a connection can be taken from
the bottom of the inlet group.
5.1.5 Drain valve
It is also recommended to install a drain valve
in the lowest point of the cold water feed to the
cylinder. This allows the cylinder to be drained
in a controlled manner should this become
necessary.
5.2 Hot Water Outlet
The hot water pipe work is to be directly
connected to the hot water outlet connection on
the cylinder, see Figure 1.
5.2.1 Thermostatic mixing valve
A thermostatic mixing valve may be required to
limit the outlet temperature. In this case, the
valve should be installed following the
manufacturer’s instructions, ensuring none of
the safety equipment has been isolated, (i.e.
make sure the connection to the thermostatic
mixing valve is taken after the safety
equipment of the inlet group).
5.2.2 Pipe insulation
It is recommended to insulate the hot water
pipe work from the cylinder to the outlets, to
reduce the energy requirements for providing
hot water. It is also recommended to insulate
all other exposed pipework, such as the T&P to
the tundish, the coil flow and return and the
cold water inlet pipes.
5.3 Discharge pipes from safety
devices
5.3.1 Discharge pipe D1
 The temperature and pressure relief valve
must be discharged directly or by way of a
manifold via a short length of metal pipe
(D1) into a tundish; and the discharge pipe
must be installed in a continuously
downward direction and in a frost free
environment. Water may drip from the
discharge pipe of the pressure relief device
and this pipe must be left open to the
atmosphere.
 The diameter of discharge pipe (D1) should
not be less than the nominal outlet size of
the safety device, e.g. temperature relief
valve.
 Where a manifold is used it should be sized
to accept and discharge the total discharge
from all the D1 discharge pipes connected
to it.
 The discharge pipe work from the
expansion relief valve must be installed
constantly falling to an open point of
discharge. It is recommended to combine it
with the discharge of the temperature and
pressure relief valve.
Note: The T&P valve is pre-sealed and if
moved the seal will be broken, should this
occur, it will need to be resealed with an
appropriate sealant (Dimplex part number
R00836-1).
5.3.2 Discharge pipe D2
For a detailed description of the discharge
pipework D2 see chapter 4.4.1.
5.3.3 Tundish
 The tundish should be vertical, located in
the same space as the unvented hot water
storage system and be fitted as close as
possible to, and lower than, the safety
device, with no more than 600mm of pipe
between the valve outlet and the tundish
(see Figure 3).
 Discharge should be visible at the tundish,
where discharges may not be apparent, e.g.
in dwellings occupied 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.
Note: To comply with the Water Supply
(Water Fittings) Regulations, the tundish
should incorporate a suitable air gap.
It is important that the tundish is
positioned away from any electrical
components.