Drainback and Pressurised Systems

There are two ways to configure the solar heating circuit, pressurised systems, where the solar pipework is entirely filled with liquid, and drainback, where the solar panels empty down when the circulation pump is not running.

The advantage of drainback lies in its simplicity and robustness - there are fewer components, filling is as simple as pouring in the solar fluid and, because the solar panels are drained when not in use, there is a reduced risk of freeze damage to the panels themselves.

By contrast, the pressurised solar loop requires the installer to use an external pump to charge the system with solar fluid, eliminate all air and pressurise the system. This process can be time consuming compared to commissioning and maintaining a drainback system.

See Also: Solar Energy Guide - Plumbing systems for solar heating

Simple Installation

Whether its a drainback or pressurised plumbing system, both share common features which make installation quick and easy. The factory-assembled wall-mounting unit greatly simplifies work on site, and creates a more professional and uncluttered finish for the solar plumbing. Installation is reduced to four runs of insulated pipework. There's very little in the way of electrical works because the electronic controller is pre-wired to the pump and the sensor lines are plug and play. (See the installation guides below for further information).

An integrated catch tank avoids the need for the installer to discharge the over-pressure relief into the drainage system - a practice which is increasingly frowned upon by both customers and Building Control.