Solex Roofing Installation Manual 39
Solex Energy Ltd +44(0)1305 837223 www.solexenergy.co.uk
Solar controller wiring, 230vac
– the solar controller should be fitted somewhere where it
can be seen and operated by the building occupiers. An airing cupboard is often suitable.
It must have a 230vac supply via a fused spur (3A), or it can be fitted with a 13A plug. The
incoming mains is wired as shown behind the controller front panel.
Solar pump, 230vac
– the controller is connected to the pump with 3 core cable or flex.
Where the wiring is fixed adjacent to the solar plumbing, then it should be high
temperature rated.
The pump is connected to relay R1. On BS4 and more advanced controllers this is a solid
state relay, which can control the pump speed.
Where several pumps are fitted for roofs orientated in the same direction, then they may all
be connected together to R1.
Where two pumps are fitted for differently orientated roofs, then the pump for Roof1 is
controlled by R1, and the pump for Roof2 is controlled by R2.
Solar controller & pump, 12v
– a 12v controller is available. This may be supplied using
a solar PV panel with a wattage in the range 30-50w. A 12v pump designed for use with
PV panels is available, which may be supplied either directly from the panel without using
a controller, or using a controller and with a small lead acid battery and charge controller to
stabilise the supply. The advantage of using the controller is more accurate control of the
pump, and therefore higher system efficiency.
3 port valve
– this controls the solar flow on systems with more than one store or heat
exchanger, and directs it to the required location. It is wired to relay R2 on BS Plus
controllers and R4 on higher spec controllers. Note any heat input device, e.g. cylinder
coil, pool heat exchanger, flat plate heat exchanger etc is termed a store in relation to
controller wiring and system layouts. See the controller manuals for specific system
layouts and connections.
On standard mid position valves with five wires, the controller relay output is connected to
the White and Grey wires together. The other connections are Blue to neutral and Green
to earth – Orange is not used. The valve therefore switches from one position to the other,
as there is no facility on the controllers to use it in the mid position state. These valves
typically only come with 1m of flex, so a junction box will usually be required.
Sensors
– the roof sensor has a black silicone sheathed lead and is mounted on the roof
as detailed in the roof section above. If there is any likelihood of lightening induced
surges, then a protection device is available.
The cylinder sensor has a light grey sheathed lead, 2.5m long. It should be located in a
sensor pocket, or touching the cylinder wall, at a height level with the top of the solar coil.
Where this is not possible it is acceptable to position it anywhere down to the height of the
centre of the coil. If it is placed too low, the system could overheat the cylinder. If it is
placed too high the system will function with reduced efficiency.
A sensor for a flat plate heat exchanger should be mounted with a good thermal
connection to the cold inlet pipe on the non-solar side of the exchanger. It may be
mounted with a jubilee clip or similar, and it is recommended that it is lagged so as to get
an accurate reading. A standard cylinder sensor may be used, or special pipe sensors are
available with a flange and clip for fitting.
