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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Plumbing Questions >> Can I add a second boiler to my existing system? https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1263217589 Message started by pryantcc on Jan 11^th, 2010, 1:46pm

Title: Can I add a second boiler to my existing system?
Post by pryantcc on Jan 11^th, 2010, 1:46pm

I would like to add a wood stove with back-boiler to my central heating system. I'd like to do it myself, I can work a spanner and a hack-saw and have no problem with the mechanical bits. I just don't understand how these things should be done to ensure that it works once it's all hooked up!

Here's what I know:

I live in a two-story house with 5 bedrooms. My current system runs off an oil boiler which is out in my garden at ground floor level. It heats 12 radiators varying from tiny to quite big. There is a hot-water cylinder upstairs which has a red pressure-vessel beside it. There's a coil in the cylinder which the central heating water passes through to make hot tap water. There are no room thermostats, the radiators have little valve/stats on them. The oil burner is controlled by a timer.

The cylinder is right beside my chimney which is directly above the living room, so I thought it would work out nicely to have a stove there with two heating pipes running up the side of teh chimney to the airing cupboard above and joining into my existing system.

You guys will probbaly need more info than this, but I'll wait for the questions so I can give precise answers!

My questions:

Can I keep my oil burner AND install the wood burner?
Can I just T into the existing pipework with the wood burner?
Do I need any additional equipment (pumps or valves or controllers) so that both systems would work together?
Can I just let the smoke from the wood burner up the chimney, or do I need one of those flexi-liners?

Thanks in advance for your help!!

Title: Re: Can I add a second boiler to my existing system?
Post by Lectrician on Jan 11^th, 2010, 3:25pm

Usually you have a completely different coil in the cylinder for the wood burner, and everything operates independently. The cylinder stat will cut out the boiler if the wood burner is heating the cylinder satisfactorily.

There all sorts of design considerations when it comes to back boilers as the heat source cannot be controlled electrically, and there needs to be somewhere to get rid of excess heat (a rad in the bathroom for example).

Scruff will be able to tell you more, but will likely advice you to get a plumber in as these things need to be designed correctly to function both safely and effectively.

Title: Re: Can I add a second boiler to my existing system?
Post by Headrush on Jan 12^th, 2010, 1:36am

This firm specialises in equipment designed for connecting multiple heat sources...

http://www.dunsleyheat.co.uk/neutralizerpics.htm

Title: Re: Can I add a second boiler to my existing system?
Post by pryantcc on Jan 12^th, 2010, 8:54am

Thanks guys! some interesting reading material. I'll have a look through it and see if I can make sense of it all.

Title: Re: Can I add a second boiler to my existing system?
Post by CWatters on Jan 13^th, 2010, 8:17am

On the paperwork side.. Wood stoves have to be installed by a Hetas registered installer or you have to make a Building Control Application and they maytry to insist you use a Hetas installer.

Title: Re: Can I add a second boiler to my existing system?
Post by pryantcc on Jan 28^th, 2010, 12:51pm

I'm not sure that this applies in Ireland, but I will check up what I need to do here in terms of the regulations.

I've been doing a bit more investigation and it now looks relatively straight forward. Here's the plan:

I intend to install this in the fireplace:
http://www.esse.com/stoves/multifuel_wood/350gs.html

And pipe it to the airing cupboard above where my two radiator circuits terminate. In the airing cupboard, I will install one of these:
http://www.esse.com/pdfs/Centraliser.pdf
to "mix" heat from my existing oil boiler with the solid fuel heat.

My existing system is closed with a pressure vessel. The instructions say I need a header tank, but I don't understand why. Can't I just have a pressure blow-off valve piped to outside from the solid fuel burner?

Title: Re: Can I add a second boiler to my existing system?
Post by thescruff on Jan 28^th, 2010, 3:43pm

You cannot install a wood burner on a sealed system. :o

It would have to be a completely separate system with a heat sink rad and a twin coil cylinder.

What is the make model of the existing boiler, it may not be suitable for an open vented system.

Title: Re: Can I add a second boiler to my existing system?
Post by heating-eng on Feb 11^th, 2010, 10:44pm

wrote on Jan 11^th, 2010, 1:46pm:

you are not allowed to do this sort of install .