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Combination Boiler - can Solar system be intergrated?

Postby covehithe » Sun Apr 15, 2007 12:03 pm

My mother has recently moved to a house where the old heating/water system was removed and replaced with a Vailant combination boiler.
She now wants to add a solar panel to heat the water. Can this be done as there is no tank, or is there someway this can be intergrated into the existing system??
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Postby Aarovic » Sun Apr 15, 2007 8:40 pm

You can install an indirect unvented or vented hot water cylinder to the boiler heating circuit. It will mean quite a lot of plumbing work. Alpha Boilers manufacture a system that works with their boilers but I have never seen one installed so I cant comment on its suitability for your mum's installation.
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Postby sparx » Fri Apr 20, 2007 8:44 pm

we have solar hotwater system which has a very well insulated hot water tank with two heating coils inside one fitted to the solar panel circuit and the other available to go to the boiler heating loop.
we don't have a boiler connected as we get enough from solar but the controls needed are quite sophisticated, as you need to stop boiler circuit from heating system during the daytime & to check at night if water heating needs 'topping up ' after dark etc.
A nice 'green' attitude, but be aware that cost of fitting parts will not be recouped within several lifetimes..... sales blurb lies!
However you don't buy fridge, TV, washing m/c & expect a pay back.....
I believe it is possible to use solar panel, if not too efficient, upstream to 'pre-heat' boiler feed water & reduce work done by boiler, there are a number of web sites dedicated to 'alternative energy'
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Postby miloc » Tue Apr 24, 2007 8:06 am

Yes, your mother will need an additional unventilated storage tank added to her existing system and some extra plumbing and electronic control system, plus the solar panel of course - a few companies do this, so look up on the net if your are stilll keen. (External link removed).

I've been researching this recently, and you need to find out from Vaillant customer services if the combi boiler your mother has will accpet pre-heated water, as this is the key. If not, then no she can't adapt it for solar. Vailant do sell solar panels and cylinders, so some of their boilers must do this, but may be not the combi boiler variety. It may just require a quick modification by one of their engineers, so get in touch with them. (External link removed)

hope thats of some help,g ood luck !

Miles Clarke.
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Postby covehithe » Fri Apr 27, 2007 2:52 pm


Thanks for your helpful advice.
I've checked with Vailant who confirm her boiler cannot be used in conjuction with solar panel.

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Postby I, Mustard Mitt » Sat Apr 28, 2007 7:40 am

Is there no way a panel can be added to increase the water temperature at the input to the boiler? It would mean less fuel to heat the water to it's required temperature. and no tank.
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Postby Eco-Save-Dave » Mon Dec 10, 2007 1:22 am

Hi Mustard,
It sounds feasible to preheat the input to the boiler but for solar you need a cylinder to store the heat from the panels and to even out fluctuations when there is no solar available i.e. at night. Also many will boilers will not accept preheated water or restrictions on the max temperature.
I hope that helps
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