Retrofit wood-fired hot water into new, oil-fired CH and HW system?

Hi all,

I'm feeling rather sheepish as I should have done my homework weeks ago, as you shall see, but I am where I am...!

We've recently bought a new house and spent the past few months renovating it, which has included a new Charnwood Cove 2 wood burner and new oil boiler, hot water tank and hot water/CH system (with expansion cylinders rather than a cold water tank in the loft). The plumber we used (who we have no problems with and have used many times before) told me that fitting a woodburner-backboiler into the system would add substantial extra cost and so, disappointingly, we decided against.

However, I've been thinking that I should have got a second opinion and that is what I am doing now. I'd be grateful if anyone can give me an idea of the feasibility and (very) approximate cost of installing a backboiler onto the Charnwood (you can get a flueboiler to fit our stove which I guess is the sort of thing we'd be looking at) and using this heat to complement the indirect hot water system which is currently heated by the oil boiler (and immersion).

Any comments gratefully received - please bear in mind that I'm not a plumber so my technical knowledge is limited.

Thanks,
Alex

Is it an unvented hot water cylinder you have? reading your post it sounds like it.

I agree sounds like unvented
You can't have an uncontrolled heat source incorporated with unvented cylinders
Only way you can do it and have mains pressure water is by a thermal store

As everything is unvented it is now a bit of a problem. Solid fuel needs to be connected to vented systems for obvious reasons.

There are a couple of ways to do it but none are particularly cheap or easy to do now.

It sound like you have left it too late now Mr Bumpkin, it would be a bigger and more expensive job and defo not DIY

You can have an unvented cylinder heated by your wood burner but you would need an open vented heating system as ecowarm has suggested it will not be cheap to do it Properly

That'll be the H2 panel then? I noticed on their website they have a version for unvented.

Many thanks for all of your comments - I may have just to leave it then and carry on forking out on oil! Thanks for your help.

Hi
Had an oil fired unvented system feeding a vented dual coil hot water cylinder & sealed radiator system.
Fitted a Charnwood insert solid fuel boiler feeding it via the spare cylinder coil, tee'd from feed before coil into pump and into existing unvented radiator run (unventing it). Check valves after each pump & standard PSV's in place.
Happy with performance ran both to max no issues.

Originally Posted by Solid Fuel

Hi
Had an oil fired unvented system feeding a vented dual coil hot water cylinder & sealed radiator system.
Fitted a Charnwood insert solid fuel boiler feeding it via the spare cylinder coil, tee'd from feed before coil into pump and into existing unvented radiator run (unventing it). Check valves after each pump & standard PSV's in place.
Happy with performance ran both to max no issues.

This don't make sense to me???

Originally Posted by Gray0689

This don't make sense to me???

Even less to me as he has posted seperate topic on backflow. So it's not running 'no issues'.

Originally Posted by SimonG

That'll be the H2 panel then? I noticed on their website they have a version for unvented.

Yeh H2 panel it is , I have done a good few of various set ups and had very good results

Originally Posted by quality

Yeh H2 panel it is , I have done a good few of various set ups and had very good results

Still haven't had chance to use one, yet. Customers tend to think great idea, tie in the heating and the stove, until they see how much it will be!

Yes this is the down side and it's not just the extra cost of the panels (which ain't ) it's extra work (which can be quite a lot) that boosts the price

The Domestic HW is using an vented dual coil hot water tank.
The original heating system was oil fired un-vented feeding into one of the coils.
A solid fuel system was fitted using the spare coil on its primary circuit, the oil fired system was turned into a vented system and a both then fed via pumps and check valves into the now vented radiator circuit