Researching solar energy for our proposed build, I note that not all advertised systems have a drainback facility. While antifreeze can cope with winter, what happens to a system without drainback when the system is not used in summer, eg the annual holiday?
In a system with drainback, are there any issues with residues "cooking" in the emptied system? Presumably in a closed circuit limescale won't occur but would a film of dried antifreeze accumulate sufficiently to impair the flow eventually?
I would be grateful for any thoughts - I find the more I learn the more questions arise!
Tony
posted on 03-05-06
Most systems dont use drainback. Why switch it off?
T Lawrence
posted on 03-05-06
Is there then no possibilty of damaging anything by leaving it running without using any of the hot water it generates - even over, say, two weeks at the time of maximum output in summer?
Tony
posted on 03-05-06
no
T Lawrence
posted on 03-05-06
That simplifies a decision - many thanks.
Nigel
posted on 03-05-06
When the system reaches maximum temperature and the collector temperature is left to rise (stagnation) the glycol does degrade and will eventually go black and will need to be replaced. This happens very slowly but the rate of decay depends on the frequency and degree of stagnation.
It would only be an issue if stagnation were to be a regular expectation. Eg in schools where there is no water use for a number of weeks during the hottest time of the year.
My glycol is three years old and is still the same colour as when it was installed and does occasionally stagnate.
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