The solar hot water drainback system

A drainback system - click diagram to enlarge.

During daylight hours the panel is heated up by solar radiation. When its temperature rises above that of the water in your hot water cylinder, the pump starts, lifts water through the panel and transfers this heat to the water in your cylinder via the pipe work.

If there is not enough useful light, the hot water has reached the required temperature or, for example there is a power cut, the pump will stop and the water in the system 'drains back' into the property to a level below the roof.

This makes the system fully controllable, fail safe and avoids the risk of the system getting too hot or freezing. For these reasons we always try and fit a drain-back system.