Our retrofit cylinder coils are an economical way of installing solar heating into an existing heating system, without changing the cylinder. The coils are fitted into the cylinder through an existing immersion heater boss.


The kit contains a screw in header, and 4m or 6m of DN12 flexible stainless steel pipe with fittings. This corrugated tube has a large surface area in contact with the water, enabling efficient heat transfer.


When fitting, the pipe is first formed into a coil of suitable size and shape required to fit the cylinder. It is then connected to the header and screwed into the into the immersion boss. Note the narrow bottom loop to enable insertion.

The inlet and outlet pipes will take 22mm solder or compression fittings, or 15mm solder fittings.