solar water heating in spain

Here in Spain we get lots of  sushine of most of the year, which makes it ideal for solar, a common problem with vacuum tube solar water heaters can be over heating in the summer.

With high pressure units it is very important to maintain the pressure relife valve, so to avoid damage if it becomes blocked and fails.

Vented units ( pre heat indirect and non pressure direct systems) do not suffer from this problem because when the water boils it will escape from the over flow vent .

It is important to remember that any unit left for a long period and let to over heat every day is not a good thing and with time will result in damage.

Vacuum tubes are very powefull and it is best to use there types of  solar water heaters on a daily basis as this will have a cooling efect and prevent damage, However if you find your swh over heating in the summer and it is in constant use , its performance can be easily reduced by blocking out the sun from some of the tubes, this can easily be done by sticking electrical insulation tape strips to the front of them . In the winter it can be easily removed to get the full performance back.

If you are going away on holiday for over a week it is important to cover all of the tubes ( in effect turning the power off as you would do with any other appliance. eg, you would not go on holiday and leave the gas fire on !!)