Willis Renewable Energy Systems

The Solasyphon is essentially a vertical heat exchanger. Solar heated water is pumped around the solar circuit, and through the primary side of the heat exchanger. The secondary side of that heat exchanger only holds about 1.8.L of water. This heats up very rapidly and as it does so, rises out of the Solasyphon under its own buoyancy. It then draws cold water in from the coldest part of the existing storage cylinder. This in turn draws the solar heated water into the top of the storage cylinder where it stratifies due to the high temperature. This process will continue as long as there is sufficient solar gain, or until the tank is full of hot water. The thermosyphon process will stop naturally when the entire cylinder is full of hot water.

Yes it suitable or connection to both vented and un-vented systems. The Solasyphon has been tested to 10bar on both the primary and secondary side.

If the cylinder has a "spare" connection at the bottom, this should be used (eg: drain point, spare tapping). The connection method is different for copper vented systems and pressurised systems. Copper vented systems - This is quickly and simply achieved using an Essex flange. This fitting is available in 3/4 inch or 22mm from most plumber's merchants.
Pressurised systems - On the pressurised systems a connection may be made using an injector tee on the mains water supply adjacent to the storage cylinder. It is important not to have any bends or elbows between the injector and the storage cylinder. A regulating valve should be fitted on the cold feed immediately before the Solasyphon.

The Solasyphon is suitable for use with most solar thermal systems both evacuated tube and flat plate.  It may be used with closed loop or drain back type systems.

The Solasyphon has been tested with up to 6m² of evacuated tube net absorber area, which equates to about 600Litres hot water storage capacity.

As with other plumbing components the Solasyphon may be affected by scale build up overtime in severe hard water areas.  Therefore as with other appliances you should consult your local supply authority about the most appropriate way to treat the water supply.

As a rule, the solar manufacturer's requirements should be followed.  Requirements will vary for different manufacturers.  Generally the cylinder sensor should be mounted below the level of the heating coil on the existing cylinder use the spare tapping if available or on the cold feed entering the Solasyphon.

This is a 15mm threaded socket for fitting a vertical support bracket.

It can be fitted below the cylinder but not above as it will affect the performance of the Solasyphon.