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Drainback System
Drainback System

A Solar Heating System known as a drainback system, or DBS, provides for the automatic emptying of the Collector and piping whenever the system is turned off or whenever the collector temperature strays outside a specified temperature range. The circulation pump shuts itself down and then the water drains by gravity to the storage tank and Heat Exchanger. By means of such drainback systems the overheating or freezing of a solar heating system can be avoided. Furthermore, the use of chemicals like glycol as anti-freeze is not necessary.

Graphics: Schematic diagram of a drainback system:

1. circuit difference exceeded, heat gain possible, pump working.

2. circuit difference exceeded, pump turned off.

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