DIY Doctor

Linking with Solar Energy storage tank

Postby Steve W » Mon Apr 27, 2009 10:26 am

I have Solar heating which is a sealed system coiled into the lower part of a new storage tank. The Gas cental heating is old, noisey and is piped into the higher part of the storage tank. I want to update my heating system to include the Solar heating but have read that the Combi system will not work with the Solar system.
1. Why can't the Solar be piped into the supply of the Combi.
2. If 1. is not possible, what would the best alternative be.

My thanks to acsimpson for quote, I still don't know if the water from the Solar heated tank can be used as a supply for a Combi boiler, does it need COLD water or mains PRESSURE.
Last edited by Steve W on Sat May 02, 2009 12:11 pm, edited 1 time in total.
Steve W
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Simply Build It

Postby acsimpson » Tue Apr 28, 2009 9:02 am

If I understand it correctly then you can't use a combi as it does not store any hot water, while the Solar system works on a stored hot water basis.

To continue using your solar system you would need to update your system with a stored hotwater system. Either a vented or unvented one. Provided the hot water storage is well insulated there is no reason it should be less efficient than a combi and with the added solar benefits it should be better.

Personally I prefet stored hot water as there are not issues with minimum flow rates for hot water.
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Postby Skids » Sun May 03, 2009 4:22 pm

Hi acsimpson

combi boilers have two sides

the IN/cold side before the heat exchanger and OUT which is hot after the Heat exchanger

All the seals on the IN side are not designed to take water above 25°C, where the out side will

You can do this however ALL combi manufactures will not guarantee the boiler if you put water hotter that 25°C into the boiler

There is a mixer on the market (GRANTUK) that blends the water down to 24°C to get around this issue however to me this deftest the point of solar hot water systems

Basically if you want solar hot water system you need a stored water system hence a system boiler to back up the solar panels


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