Wood Oil Combo Boilers

[BillM2]

We recently moved into a 100+ yr old, 2,000sq ft house which is need of a new boiler. I've just installed a pellet stove on the first floor and it's doing an adequate job of heating the house. We're able to keep the house 68-70 degrees without too much difficulty, but am going through the pellets pretty quickly (1 1/2 to 2 bags per day coldest days) plus I use the oil mornings/evenings and for domestic hot water. We have property with lots of trees ready (oak and maple) for harvest and plenty more from neighbors. I'm considering a wood/oil boiler for our baseboard and domestic water use. Right now, we have an old Peerless that sucks oil like an old Buick.

So my question is, who has experience with this combo units, how well do they work, what are some of the headaches, etc? I'd have to keep a cord of wood in my basement, which is a dry area and there's concern about pests making a home indoors, is one of our questions. I'd like to have the option of burning wood in addition to the pellets, when needed, oil when absolutely needed (such as when we are away).

I am looking at this brand of boiler to start> (broken link removed to http://mainewoodfurnaces.com/CC500.shtml)

I can't install an outdoor boiler -- against local code.

Thanks much!

 

[pybyr]

Nearly all combo units I am aware of makes substantial compromises in efficiency on at least one of the fuels-- sometimes both. The unit you linked to looks to be a non-gasification boiler, and so will not be nearly as efficient on wood use as some of the more current designs; I suspect it won't set any records on efficiency at using oil, either. Not trying to slam the maker- it looks like a robust, well made unit-- it just appears to be state of the art as of about 20+ years ago...

The unit i'd take a hard look at if I wanted to burn mostly wood, but have a fall-back to oil, is the Varemaronen, which lets you swap boiler doors to fit an oil or pellet head when you can't run wood. It's a very efficient wood gasification boiler that also lets you have that second fuel option, with little to no "hit" on efficiency, as long as you don't mind the hands-on task of swapping the oil burner head on:

(broken link removed)

 

[steam man]

I think you may want to evaluate your heating needs. Does the house need sealing/insulation? If not, do it. Seriously have the Peerless checked for operation/efficiency. If it is bad you may want to upgrade it to a decent unit. I like separate units though it sounds hard to justify using wood part time when you burn pellets. I just think with a combo unit you would be trading one inefficiency for another.

 

[BillM2]

Nearly all combo units I am aware of makes substantial compromises in efficiency on at least one of the fuels-- sometimes both. The unit you linked to looks to be a non-gasification boiler, and so will not be nearly as efficient on wood use as some of the more current designs; I suspect it won't set any records on efficiency at using oil, either. Not trying to slam the maker- it looks like a robust, well made unit-- it just appears to be state of the art as of about 20+ years ago...

The unit i'd take a hard look at if I wanted to burn mostly wood, but have a fall-back to oil, is the Varemaronen, which lets you swap boiler doors to fit an oil or pellet head when you can't run wood. It's a very efficient wood gasification boiler that also lets you have that second fuel option, with little to no "hit" on efficiency, as long as you don't mind the hands-on task of swapping the oil burner head on:

(broken link removed)

What more modern designs are out there that deliver better efficiency?

The Benjamin's overall dimensions would fit down my stairs to the basement, which is partly why I was looking at it and there are claims both fuels can fit up the same flue. Some of the others are giant and wouldn't make it down.

 

[Como]

If you look on that link, the Boiler mentioned would seem to meet your requirements, my guess is that it will cost a bit more but definitely a case of you get what you pay for.

Presumably the issue with boilers outside relates to OWB's rather than Gassifyers?

 

[timberbuilt]

Look at the WoodGun from Alternate Heating Systems. It has an optional fuel oil burner attachment with auto switch over. I'm sure the oil burning is very inefficient but it would keep your water warm while your away. When I was shopping for my boiler I thought the same as you, multiple fuel would be a slick setup. I came to realize that wood boilers are not built for other fuel sources and when used are very inefficient. It also seemed like the options for multiple fuel attachments would cost the same as a low end propane boiler. So instead of putting all my eggs in one basket I went with a gasification boiler and I'm going to install a cheap propane boiler to run when I'm away and can't stoke the wood boiler. There's a few logistical problems to overcome with this but with this game there always will be no matter what route you take.

 

[muncybob]

If you have the space to run dedicated source boilers(1 wood & 1 oil, etc.) then do that! As mentioned they will probably be more efficient but also if one fails you still have one to fall back on. We did not have the room for 2 boilers but we wanted 2 sources of fuel and the Wood Gun was one of the few I looked into that would fit into our basement entry. I can't say how efficient the oil side is since we rarely use it but after last year and so far this year we are very happy with the efficiency of the wood boiler. Wood supplies our heat and hot water during heating season and electric supplies hot water other times since oil is a very inefficient way to heat your domestic hot water.
Just like with most new things, there was a learning curve to get through but we now are comfortable with the operation of the boiler and believe it was the right financial decision for us.