Outdoor boiler only....wood selection

[btammo]

Heres a couple questions.

What wood is best for you?
Do you burn green or seasoned wood?
Which lasts longer and do they produce the same amount of heat?
Do you find that bigger chunks last longer in the firebox than a bunch of smaller pieces?

I have been experimenting to find the best loads. I am new to the outdoor wood boiler and am trying to be as efficient as I can with the wood.

Thanks

 

[Eric Johnson]

Welcome to the Boiler Room, btammo. What kind of boiler do you have?

As a general rule, you're always ahead with dry wood compared to green or wet. That's because the moisture has to be converted to steam to exit the system, and converting water to steam takes a lot of extra energy. And it's all going up the stack, unused, in the form of steam.

As for wood type, denser hardwoods are better than softwood or less dense hardwoods. You can't always tell by weight if the wood is green, as some non-dense hardwoods (black cherry and poplar, for example) contain a lot of water when green. When the wood is dry, the heavier chunks are the denser ones. Since you're in the Southern Tier, I'd try to stick with as much red and white oak, hard maple, hickory, beech and black locust as possible. Try to stay away from soft maple, black cherry, poplar basswood, etc.

With most stoves and boilers, bigger wood lasts longer but doesn't burn as hot. Most of us have a mixture that we try to use to its highest potential.

 

[slowzuki]

In an OWB, the only way you can cleanly regulate the output is the surface area of the wood burning. So, small split dry pieces will lead to damper closed with smoke billowing. Big dry chunks will burn cleaner and longer and produce more heat than any other option if you get it up to temp quickly with small dry stuff.

Wet wood produces lots o smoke in any config, but may last a bit longer while doing it.

 

[JustWood]

My dad just bought a Central Boiler this last fall and has been burning since 1st of Nov. I supply all his wood from our pallet shop ( fairly green) and wood from prosessors (1-2 years dry) . He claims the greener wood from pallet shop makes for longer burns . We saw and process about 90% Beech and 10% Maple. I use a loader with a 2.5 yard bucket to deliver his wood next door ,he usually goes through 1-3 of these a week (all 4/4 lumber trimmings) depending on the weather.

 

[dumbodog00]

I have a Hardy OWB. The wood I am using has been cut and drying since May. I have found the larger the wood, the better. If I use two large shovels of coal (about equal to two five gallon buckets) and big chunks of wood, I was getting a full 24 hrs out of a load. That is when it was 0 outside all day and heating a 2400 sq. ft. house at 72. I am currently using slab wood and use two wheelbarrows a day when I fill it to the max. I feel that the bigger the wood is the better. It has not been that cold yet this year.

 

[pdboilermaker]

I have a Woodmaster 4000 so it is fan draft. I find that in the factory settings, it was difficult to burn anything much over 8" in diameter so anyhting bigger I had to split. This year, I adjusted the settings to off at 170 deg, on at 140 deg and find that I can burn anyhing that I can throw in which is say 20" diameter.

As far as wet/dry - dry gets your water temp up higher, faster than wet wood because you dont have to "boil" the water out.

A simple rule of thumb is this - the heavier the wood the better, or if you dont know the weight and are looking at a tree, the bigger the leaves the better. But any wood that is free wood is the best. You can usually find it cut up after storms, by the local power company etc.

 

[btammo]

Excellent information. I have a variety of wood right now. I have found that the unsplit pieces seem to last quite awhile compared to the same type of wood that has been split to handle, although close to the same size. I try to put a mix of split pcs and round pcs in at the same time. it is giong to be super cold out this weekend so I will experiment in close to 0 temps. Weather has been pretty mild here over the past week or so. There were some days that i was going 24 hrs on 6 or 8 pcs of wood.

 

[mikeyny]

just to clarify one thing first. Dry wood is far superior to any wet wood, no matter what species. Some boilers are more tolerant to burning wet or green wood than others, but pound for pound, dry wood is much better. Green or wet wood only lasts longer because it takes some time to burn off the water. You definitley get many more btu's from good dry wood. From what I know you get the same amount of btu's from 1 pound of wood, not matter what species. One pound of good dry oak may be 16 inches long and only 4 inches round but 1 pound of popular wood may be 16 inches long and 16 inches round, same weight, same btu value but big difference in size. I can never seem to compile enough good dry wood for an entire season, so I end of burning a fair amount of green wood out of necessity. Keeping a good stack of wood for a year in advance is difficult, not to mention the space it takes up.

Mike

 

[Eric Johnson]

I think that's right, Mike. Wood is wood. It's just that different species are packed more tightly than others, so obviously, you'll get more btus per volume with the denser species.