The panels collect energy from the sun which heats the fluid in the solar panel.

When the fluid in the panels is hot enough, the pump station circulates the hot fluid around the system.

The hot fluid is pumped around the coil at the bottom of the twin coil cylinder and heats the potable (or mains) water held within the cylinder for domestic use.

If the temperature sensor in the cylinder detects that the solar panel hasn't collected enough energy to heat the hot water to the required temperature, that's when the boiler will fire up, heat the top coil of the cylinder and top up the temperature of the hot water so that it comes out of your taps at the temperature needed.

The solar controller is the brains of the operation, managing the solar system during daylight hours, enabling you to time your hot water, just like a heating programmer, and measure the amound of energy you have gained from the sun.