This is the simplest solar system which works in conjunction with your boiler by means of your solar water cylinder heating up. This is achieved in the same manor as  (combi boiler thermal store) but you use the hot water directly from inside the solar cylinder. This is the best and most efficient way to install solar as your boiler will only operate to top up the already heated water when the solar cylinder heating is not up to temperature. Because we can achieve high temperatures in the solar cylinder on a regular basis we again use a TRV mixer valve to bring temperatures down to an acceptable range of 40 to 55 Celsius as to prevent scalding hot water at the taps/shower. The solar system again is carefully balanced and controlled using a Resol solar controller and pump station.