Hybrid Car – More Fun with Less Gas

Warm feed to combi-boiler (UK question) - Page 2

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Posted by News on September 13, 2004, 7:20 pm

The ECo-Homtec does this.  They have a dedicated solar feed model.

ECO-Hometec is Dutch, well they re-badge boilers made by MAN of Germany, the
diesel engine and truck maker. They are a class act.

To the US people on the group, a combi in European terms is a one box
solution, usually a white box on a wall but not always, that provides hot
water for hydronic heating and instant on-demand hot water using not
cylinders or tanks. I believe a combi in US terms is a boiler and hot water
cylinder combined, which are usually very large.

Posted by Mike Smith on August 23, 2004, 9:30 pm

You need to source a fully modulating combination boiler.  The _fully_
modulating bit is important as even a low heat input into already hot solar
heated water MIGHT make it boil!  Most of the boiler manufacturers will do
one - if you insist on a combi boiler that is - most of the manufacturers
quote flow rates based on a 35degC rise, which in winter in UK is just a

If you want to use the solar water to pre-heat the combination boiler, you
will need to be sure that the cylinder is suitable for mains pressure - in
the UK you have to fit a fully WRC approved unvented product or you are
breaking the law.  You cannot just take a standard cylinder, fit a safety
valve and pipe it into a combi boiler.

This is one law that makes sense - if the tanks cant take the pressure they
can burst - nasty business at the best of times, and fitting an unlicenced
product can invalidate your house contents and building insurance!

You might just be more effecient getting a dual coil unvented cylinder and a
standard condensing boiler.  The ClearSkies website shows the names of
manufacturers of approved products for solar thermal cylinders.

http://www.clear-skies.org/manufacturers/RecognisedProducts.aspx?intTechnologyID $

the products SC2011 - 2014 in the list looks pretty interesting :)

If you want details on our products, drop me an email and I will get you the


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Posted by Roland Butter on August 23, 2004, 11:14 pm
I'd thought of that - and I'm still trying to decide which way to jump.
Roland Butter :- There's nothing like a knob of butter.

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