6
4.7. Pipework connections
–
All Pipework connections to the cylinder
MUST
be made in accordance
with Fig 4.1, the secondary return being optional.
4.7.1 The
SCX Solar
unvented cylinder must be installed by a competent person with appropriate
qualifications and registration for the installation of unvented water storage heaters.
4.7.2 The cold water feed to the cylinder must be fed through the pressure reducing valve, take care
to install this in the correct direction (see arrow on side of valve) and then the pressure relief
valve, with the expansion vessel Tee’d off between the pressure relief valve and the cylinder.
4.7.3 For the single coil cylinder the immersion must be connected and suitably controlled to bring
the temperature of water to 60
o
C following heating by the solar source.
4.8 Hard Water Areas –
In hard water areas it is advisable to use a water softening device to
minimise scale build-up. Periodically the immersion should be removed and scale scraped way from
the bottom of the cylinder to avoid scale surrounding the immersion and causing failure.
5. Primary circuit installation
5.1.
Dimplex Solar cylinders are suitable for connecting to a solar collector system and where a twin
coil is present, to a gas or oil central heating boiler.
! Solid fuel or wood burning boilers, and gravity circulation systems MUST NOT be used on
the primary circuit of an unvented hot water system!
5.2. Systems design –
The cylinder must be installed in accordance with the solar installation
instructions for connection to the primary flow and return.
5.3 Two-port Motorised valves –
The SCx Solar range of cylinders must only be connected to solar
installations containing a hydraulic station with two non return valves (one in the flow to the collector
and one in the return), that will prevent thermal siphoning of the heat transfer fluid when the pump is
switched off. Where two non-return valves are not present or a hydraulic station is not used a second
twin port valve must be installed into the flow of the solar coil and wired to the lower twin-port valve.
The SCx cylinder comes with one two-port motorised valve, which should be connected in the flow to
the auxiliary coil and wired to the upper twin thermostat of the cylinder.
5.4 Solar Pump
– The lower twin thermostat should be connected in-line with the solar pump power
supply.
6. Secondary circuit installation
.
6.1. Connections
. Secondary circuit
connections
MUST
be made to the cylinder in accordance with
Fig 4.1/4.2. A drain cock (not supplied) should be fitted in the cold water inlet to facilitate draining of
the cylinder.
6.2
.
Cold water supply –
Where possible, for best results, the cylinder should be fed by an
uninterrupted 22mm supply pipe into the pressure reducing valve (PR valve) with a supply pressure of
between 3 and 12bar maximum. The cylinder should not be used on any system with a supply
pressure below 1.5 bar and a flow rate of less than 20litres per minute.
6.3. Temperature and pressure relief valve
– The temperature and pressure relief valve (T&P
valve) is supplied factory fitted to the cylinder. The TPV must not be removed from the cylinder or