Playing safe with heating

PUBLISHED : Friday, 07 January, 1994, 12:00am
UPDATED : Friday, 07 January, 1994, 12:00am

WHAT is meant by a ''drainback'' solar water heating system? A drainback type of solar system often is used in the areas that frequently have freezing weather in winter. In this type of system, the water in the solar collector and exposed piping drains into an insulated reservoir tank whenever the pump shuts off.Because of this, there is no water in the collector or the piping when the temperature drops below freezing, so there won't be any damage to the system.

Another type of freeze-protected system is the ''indirect'' system, in which an anti-freeze solution circulates through the collector, and a product called a heat exchanger transfers the heat from the solution to the water.

The heat exchanger keeps the anti-freeze from mixing with the potable water. In this type of system, there is only the anti-freeze in the collector, never water, so freezing conditions won't damage the system.