Looking for as much info as possible on multi-fuel boilers.

[Tm.mullaney]

Hello all. We just bought a house that has a 50 year old gas boiler feeding 8 radiators. It is a gravity fed system that was once used for a coal boiler. Our goal is to find an indoor wood burning/ gas boiler and integrate it into the existing system so as to heat the house with gas when we are unable to feed the wood boiler. We are just beginning our research so any information IE: brand names, user testimony, things to be aware of etc. would be greatly appreciated. Thanks in advance for your help.

 

[jebatty]

As we are proud to announce, you have come to the right place. Start searching, do your homework - there's "tons" of info on this forum, lots of literature available from mfr's and dealers, and when you have it narrowed down, we all will have a focus on how to help you. Otherwise, your request is a bit like "I want to buy a car, tell me all about cars and help me choose." As you can see, rather open-ended.

 

[__dan]

If you have utility gas available, you have a no brainer. Just put one of these in, condensing rated , OAT / ODR hot water reset built in, and forget about having to burn wood. Modulating gas fire, outdoor hot water reset, should work pretty good with the cast iron radiators. Gas is the best fuel.

http://www.weil-mclain.com/en/weil-mclain/pd-wm-97-wall-mount-gas-boiler/

If you want to process firewood, sell it to people on oil, electric, or propane.

 

[DBoon]

Gas availability opens up a lot more possibilities for venting the combustion gases. I would instead think about starting with a small gas boiler that is vented to the outside through a side wall (perhaps a condensing-type that was mentioned above) and then add a wood boiler to that later. That would keep your chimney available for the wood boiler, when you install it. It would also give you time to do your research on the wood boiler setup and get a 2-3 year supply of 2 year dried wood ready to burn. You will be very unhappy with the performance of any wood boiler that burns the typical "seasoned" wood sold by wood dealers.

 

[pbvermont]

good advice from DBoon. don't get a combination wood/gas boiler. separate units dedicated to single fuel, with totally separate venting.

 

[Hydronics]

As mentioned, combo units are less efficient on fossil fuel because the wood burning typically reduces heat transfer ability by creating an ash or creosote layer. The exception would be combo units with separate heat exchangers.
You might consider this: (broken link removed to http://www.newhorizonstore.com/Products/142-biomass-combo-boiler.aspx)
I don't believe anyone here has one though, so no feedback I'm aware of. There are satisfied non combo owners though.

 

[Tm.mullaney]

good advice from DBoon. don't get a combination wood/gas boiler. separate units dedicated to single fuel, with totally separate venting.

My chimney is in the center of the house and has three flues in it. One for the first floor fireplace, one for the current boiler and one that's not being used. So venting isn't really an issue but this is all good information. I just assumed that these combo units were two separate boilers in one and never realized that they could use more gas when not burning wood than a standard gas boiler.

Gas availability opens up a lot more possibilities for venting the combustion gases. I would instead think about starting with a small gas boiler that is vented to the outside through a side wall (perhaps a condensing-type that was mentioned above) and then add a wood boiler to that later. That would keep your chimney available for the wood boiler, when you install it. It would also give you time to do your research on the wood boiler setup and get a 2-3 year supply of 2 year dried wood ready to burn. You will be very unhappy with the performance of any wood boiler that burns the typical "seasoned" wood sold by wood dealers.

 

[Tm.mullaney]

As mentioned, combo units are less efficient on fossil fuel because the wood burning typically reduces heat transfer ability by creating an ash or creosote layer. The exception would be combo units with separate heat exchangers.
You might consider this: (broken link removed to http://www.newhorizonstore.com/Products/142-biomass-combo-boiler.aspx)
I don't believe anyone here has one though, so no feedback I'm aware of. There are satisfied non combo owners though.

Thank you. This is what I'm looking for. For some reason information on these boilers is hard to come by.