Solex Roofing Installation Manual 28
Solex Energy Ltd +44(0)1305 837223 www.solexenergy.co.uk
The solar circuit connections are pre-installed into the tank on the short side. The float
valve supplied must be installed through a hole 200mm above the tank base. This float
valve is plumbed to mains water (via an isolating valve and double check valve, also
supplied) to keep the tank topped up and to replace any water lost by vapour diffusion
through the silicone absorber. An overflow is required (22mm tank fitting supplied)
which must be installed right at the top of the tank, using copper pipe.
The tank should be located so that the working level line of the tank is a minimum of
500mm below the bottom of the solar roof, so that the water in the roof may easily flow
back into the tank. (A label showing the working level is supplied with the tank.)
The tank should also be not more than 4m below the highest point of the solar roof
area. This is so that the pump is able to pump the water efficiently to the top of the roof
when priming the system. Systems where this measurement is exceeded will not
prime. It is acceptable to use two pumps in series to increase the head in systems
where this 4m is exceeded, or in systems where the pipe layout leads to airlocks. For
future reliability, systems must always be able to self-prime without intervention.
2.
Pump
– a bronze type pump is used to move the water in the solar circuit. Cheaper
standard central heating circulators
may
be used, but their life will be reduced by
corrosion due to air diffusing into the water through the silicone absorber.
The pump may be installed either in the flow or return pipework. It must be installed as
per the manufacturer’s instructions, which almost always means with the rotor axis
horizontal and the electrical connection box at the top. Munsen ring pipe clips are
supplied to aid mounting the pump if necessary. The pump electrical supply is taken
from the controller. The pump should generally be set to maximum speed.
One standard pump is sufficient to supply 30m
2
of roof. Where the roof exceeds this,
two or more pumps operating in parallel may be used. This is more reliable and less
expensive than using a single larger pump. A flow rate of at least 0.5 LPM/m
2
of solar
roof needs to be achieved.
Systems which will not prime due to the 4m height (above) being exceeded, or where
the layout of the pipes is not ideal and leads to airlocks, may be fitted if necessary with
two pumps in series (or 2x2 pumps for systems >30m
2
).
3.
Plumbing pipe
– the solar circuit may be plumbed in any normal pipe system,
including copper with soldered, compression or pushfit joints, or in flexible PEX pipe.
The reason that any pipe material can be used is that the system is unable to pump
water exceeding 100
o
C. The use of polybutylene pipe is not recommended as the
temperature rating for this type of pipe is usually lower than for PEX pipe. 22mm
plastic PEX pipe will supply up to around 40m
2
of solar roof, depending on pipe runs.
Normal pipe lagging may be used outside the roof area, and must be used where the
pipes are subject to freezing. Within the hot zone, if lagging is used it must be the high
temperature solar rated type.
4.
Roof inlet
– the transition to the silicone tube for the roof inlet is made by crimping the
silicone tube onto either 22mm plastic pipe with a pipe insert, or onto metal pipe. If
connecting to plastic, there should be a minimum of 500mm of silicone tube outside of
the hot zone of the solar roof.
