View Full Version : RE: Anyone have experience with wood boilers or multi-fuel boilers



firefighterjake
09-26-2005, 09:10 PM
I am looking at the possibility of installing an outdoor wood boiler or a combination wood boiler/fuel oil boiler inside and hooking them up to my existing baseboard heat . . . does anyone have any experience with either one of these type of heating units?

Sudonim
09-26-2005, 09:16 PM
The only thing I've read about outside wood boilers is that, unless you have a large demand (school, business, really big house), you don't get the efficiency that you should. They are designed to run fairly long time periods (due to energy expended getting them up to temp), so if you are firing it up, house gets warm, shut it down, you might be better off with a different system. Again, this is only stuff I've casually read, no first hand experience. Stay warm :eek:

Cache'n Jacksons
09-27-2005, 06:28 AM
I don't have any direct experience with them either, but grew up in a house heated that way, with a homemade wood furnace connected to an old coal boiler. It's a lot of work, but can pay off if you have access to cheap wood and have a large or poorly insulated house. The modern systems run much more efficiently due to an electronic control module that monitors flue temperature and hot water demand, and adjusts the damper accordingly. I have heard that they can go as long as 48 hours between refills depending on quality of wood being burned and demand for heat. One such system is made by Aqua-Therm (http://www.aqua-therm.com) and I believe my father still has a distributorship with them. You may be able to contact them and they can put you in touch with someone local using the system.


On a related note, this Saturday is the National Tour of Solar Homes Open House (http://www.nesea.org/buildings/openhouse/). You can go here (http://www.nesea.org/buildings/openhouse/listings.php?action=Search) to find a list of sites near you. I am hoping to stop by Bill Lord's Solar Home (http://www.solarhouse.com) in Kennebunk to check it out. His website has tons of info on getting free energy from the sun!

brdad
09-27-2005, 11:12 AM
I know someone who has an outdoor unit - it was used to heat both their house as well as a trailer their parents lived it. They use it year round, obviosly just for domestic hot water in the summer. I also helped my father install an indoor wood boiler last year. I had gotten it off a job and his 1800's hot air wood furnace finally gave out. Anyway, we just hooked it up quick to a few cast iron radiators and some baseboard since the oil furnace is hot air. It heated real well. In fact, he had trouble keeping it throttled down it worked so well. We considered putting a big radiator in the basement to carry off some of the excess heat, but did not get to it. Once he got used to how and when to fill it, he rarely had trouble with the temp/pressure relief blowing off. As the last post states, the newer ones with better draft controls probably help a lot with this problem.

I think the outdoor boiler can be a great idea, but I question how long it takes to pay for itself. They don't give the units away, wood isn't cheap unless you cut it yorself, the entire system will have to be filled with apx. 50% anti-freeze (unless you use a heat exchanger so the current system is isolated from the wood system), the underground piping can get expensive when properly buried and insulated, and if you want it to work when the power goes out, you'll need to invest in a generator, or a battery/charger/inverter setup to operate the pump(s). I used the inverter setup on my father's and it works quite nicely, though.

There are several ways to hook the system up, but circulating the wood boiler water through the oil burner allows you to utilize existing electrical controls, thermostats, and pumps.

Do you know how big a unit you will need? What is the BTU of your current boiler, and how well does it heat your house?

firefighterjake
09-27-2005, 12:04 PM
Brdad . . . right now I'm leaning towards an indoor wood/oil boiler combination, such as the one made my Tarm (I still need more info on this though . . . I suspect they're quite expensive). I still haven't ruled out the outdoor boilers though.

Originally my wife and I were considering a woodstove or fireplace insert, but due to space restrictions and cost of putting in a decent-looking chimney that option is out . . . hence the reason I'm looking at these other options.

Getting wood will not be an issue since my family owns a decent amount of land and we've selectively cut off it for years. In some ways believe it or not I actually miss cutting, splitting and stacking firewood . . . it took time, but it always gave me a certain sense of satisfaction.

I'm unsure of the size in terms of BTU, but I figure my house is between 2,000-2,500 square feet.

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Sudonim . . . so far some of my research seems to indicate the same thing you said . . . that the outdoor boilers are not as efficient as other heating units.

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Cn'J . . . solar probably is the way to go . . . but from what I've seen the technology is still rather expensive even with tax credits and what have you.

DiverDave1998
10-20-2005, 05:36 PM
I have a wood boiler that hooked into my oil boiler works well your welcome to come check it out

Beach Comber
10-20-2005, 06:34 PM
In some ways believe it or not I actually miss cutting, splitting and stacking firewood . . . it took time, but it always gave me a certain sense of satisfaction.

I used to heat with wood years ago and miss the cutting and splitting. I didn't run the chainsaw, but there is something about throwing those 4 foot logs onto the saw horse and then slinging the cut-up pieces into ever growing piles that makes me smile. Then the splitting and stacking! A sense of satisfaction to see all that would cut, split, and neatly stacked waiting to be taken in to the wood stove! Ahhhhh - a pleasant thought. Now I just walk over to the thermostat and turn the heat up or down and write out a check to Northern Utilities each month. Borrrrrrring

WhereRWe?
10-20-2005, 06:39 PM
Brdad . . . right now I'm leaning towards an indoor wood/oil boiler combination, such as the one made my Tarm (I still need more info on this though . . . I suspect they're quite expensive). I still haven't ruled out the outdoor boilers though.

Originally my wife and I were considering a woodstove or fireplace insert, but due to space restrictions and cost of putting in a decent-looking chimney that option is out . . . hence the reason I'm looking at these other options.

Getting wood will not be an issue since my family owns a decent amount of land and we've selectively cut off it for years. In some ways believe it or not I actually miss cutting, splitting and stacking firewood . . . it took time, but it always gave me a certain sense of satisfaction.

I'm unsure of the size in terms of BTU, but I figure my house is between 2,000-2,500 square feet.


Jake -

You don't want a "combination unit". In fact - I'm not sure you can even get them now. You have to have separate chimney flues for the wood and oil units (insurance rules). Best bet is to get separate units - it's what I have and it works great.

Until the rise in fuel prices, I used my oil boiler to heat water in the spring/summer as it was cheaper than electric. Wood boiler does it all in winter. We also like it because when we go off on 2-3 day caching trips, the oil kicks in until we get back.

But I have heard good reports about the outdoor wood boilers - although I haven't had any direct experience. The best thing I've heard is the long burn time and the fact that youcan use ANY wood. Got a lot of old pallets? LOL!

WhereRWe?
10-20-2005, 06:54 PM
I used to heat with wood years ago and miss the cutting and splitting. I didn't run the chainsaw, but there is something about throwing those 4 foot logs onto the saw horse and then slinging the cut-up pieces into ever growing piles that makes me smile.

Good exercise, too! LOL! I cut/split/stack 8-10 cords per year. I cut a lot on my own property, but can't get that much by myself, so I usually buy tree-length.

This year I've got loggers cutting my land, and they've already brought out 10 cords for me @ $33 per cord (hauled to a wood yard next to the house). Can't beat that...

Hiram357
10-20-2005, 07:17 PM
I agree about cutting wood, there's nothing like plunging a chunk of steel into a tree repeatedly then tossing it around like a couple of fleetwood mac records/frisbees... unfortunately living in an apartment I only get that joy every so often when I go camping of visit family that cuts their own wood, and a note to others that live in apartments... landlords get really mad when you fire up a chainsaw in the building and go after the trees and shrubs by the parking lot, and remember the best defense is to act like you cant speak english. :D

Trezurs*-R-*Fun
10-20-2005, 08:11 PM
I agree about cutting wood, there's nothing like plunging a chunk of steel into a tree repeatedly then tossing it around like a couple of fleetwood mac records/frisbees... unfortunately living in an apartment I only get that joy every so often when I go camping of visit family that cuts their own wood, and a note to others that live in apartments... landlords get really mad when you fire up a chainsaw in the building and go after the trees and shrubs by the parking lot, and remember the best defense is to act like you cant speak english. :D


Maybe you could go help WhereRWe? I'm sure he would welcome the help.

mainesurveyor
10-21-2005, 06:18 AM
I missed this whole thread when it came out. It just showed up under new posts this morning.

I have an outdoor wood furnace (boiler) and I think it's the best investment I've every made (except my wife, of course!!). I've had my Heatmor furnace operating for six or seven years right now (lost track of time for everything while in Iraq). I'm off to work right now but I'll repost tonight and gladly answer any questions anyone may have.

--Mike.

firefighterjake
10-21-2005, 06:21 AM
Whererwe and Diver . . . what is the name brand of the wood boiler that you have? Can these wood boilers be hooked up in tandem to any brand of oil boiler . . . or does it have to be a specific type? Also, where did you purchase them?

WhereRWe?
10-21-2005, 07:32 AM
Maybe you could go help WhereRWe? I'm sure he would welcome the help.

Yup. You can use my chain saw, too. Even put a new chain on it for you.

:D :D :D

WhereRWe?
10-21-2005, 07:45 AM
Whererwe and Diver . . . what is the name brand of the wood boiler that you have? Can these wood boilers be hooked up in tandem to any brand of oil boiler . . . or does it have to be a specific type? Also, where did you purchase them?

My wood boiler is a "New Yorker" boiler. Small, about 4' high by 3' square, takes a stick of wood 16" long, and the door is 8" high by 11" wide, so I can get a good sized stick in (about as heavy as RULOST2? can lift, anyway). I'm not a HVAC guy, but looks to me like you can hook it up to any oil boiler - it's just the hot water line that is connected. They operate independently, but the oil will kick in when the wood fire goes out. Actually I keep the oil turned off unless we're going to be away. We go to bed early (8-ish), and the wood won't last until we get up (we don't mind a cool start) and the oil would usually have come on in the early morning if we didn't shut it off.

We're rebuilding an old farm house (no running water or central heat when we started), so we hired a local plumber to plumb the whole house and a local HVAC guy to put in the heating system. The system really isn't complex, and you could talk to any HVAC guy about one.

We've had the system for 14 years, and the only service was to replace a set of cast iron liners in the fire box (I did that myself), and to have the oil burner serviced every 2-3 years.

DiverDave1998
10-21-2005, 09:06 AM
Jake mines a home made one and it sits beside my oil boiler its set up so when the water in the wood boiler gets to 140 the it circelates to the oil boiler and when that gets to 140 it will go though the house and if your not home and the fire goes out the oil boiler will kick on.one draw back is if the power goes out after ya load it it over heats and the water dumps out the saftey .

WhereRWe?
10-21-2005, 09:40 AM
Jake mines a home made one and it sits beside my oil boiler its set up so when the water in the wood boiler gets to 140 the it circelates to the oil boiler and when that gets to 140 it will go though the house and if your not home and the fire goes out the oil boiler will kick on.one draw back is if the power goes out after ya load it it over heats and the water dumps out the saftey .

In most systems, when the power goes off and the circulator pumps don't work, you can open a couple of valves and the hot water will circulate by gravity. You can't control the heat in the house, but at least the safety valves in the boiler won't let off and fill your cellar with steam and hot water. (Been there, done that MANY times before the HVAC guy showed me how to open the valves...) :eek: :eek:

DiverDave1998
10-22-2005, 12:29 AM
ya mine has automatic vavles but i rezoned last year and i didn't and anymore auto vavles some day when i get tired of hearing the air in the pipes i will add some. or was the the ex i was hearing.

mainesurveyor
10-22-2005, 09:45 AM
All of the following pertain to outside wood boilers and my unit (Heatmor) in particular. Other outdoor wood boilers might operate slightly differently. I don't have any experience with indoor wood boilers or combination units.



The only thing I've read about outside wood boilers is that, unless you have a large demand (school, business, really big house), you don't get the efficiency that you should. They are designed to run fairly long time periods (due to energy expended getting them up to temp), so if you are firing it up, house gets warm, shut it down, you might be better off with a different system.

This can be true. The burn cycle is controlled by aquastats on the water jacket around the firebox. Mine is set for 170 (cut-in) & 190 (cut-out) and the burn time while water circulates through the baseboards is 10 minutes. I have an old farm house, approx. 2500 sq. ft., with about half of it remodeled to modern (insulation-wise) standards. With a well-insulated, smaller home that retains its indoor temperature well the outdoor furnace might cycle a few times to keep the water in the furnace itself at temp. inbetween heat cycles in the house. These cycles last less then 5 minutes though.



...I have heard that they can go as long as 48 hours between refills depending on quality of wood being burned and demand for heat....


In the spring and fall, when my home demands heat only a couple times a day, I might only load the firebox every two or three days. In the deep of the winter, when it seems like spring will never arrive, I load the furnace in the morning before I go to work and once again around supper time.


...I think the outdoor boiler can be a great idea, but I question how long it takes to pay for itself. They don't give the units away, wood isn't cheap unless you cut it yorself, the entire system will have to be filled with apx. 50% anti-freeze (unless you use a heat exchanger so the current system is isolated from the wood system), the underground piping can get expensive when properly buried and insulated, and if you want it to work when the power goes out, you'll need to invest in a generator, or a battery/charger/inverter setup to operate the pump(s). I used the inverter setup on my father's and it works quite nicely, though.

There are several ways to hook the system up, but circulating the wood boiler water through the oil burner allows you to utilize existing electrical controls, thermostats, and pumps....

brdad is right. The units are not cheap and there is a wide difference in the price range. Total cost for my complete setup a number of years ago was around $6000. Sounds like a lot until you figure that I used about 1500 gals. of heating oil a winter so the payback time for me then was 3-4 years. With the price of heating oil today, that payback would be less than two years. Now, although I have about 70 acres I could cut wood from, I don't have time between work and my children's schedules so I but tree length hardwood for around $80 a cord (I use 8-10 cord a year). I save thousands of dollars a year! There is some work involved cutting the wood and stacking it. The firebox in my furnace is 3' long but I cut 32" sticks for convenience in loading. There is no splitting and the furnace will burn any kind of wood, green or dry. Obviously I burn more green wood for the same BTUs than seasoned, but I still only load the firebox twice a day. The only inconveniece is keep the snow cleared around the furnace and a path from the house to the furnace. I sited my furnace so I could plow all the way around the woodpile and the furnace. I don't like to shovel!

As most of the posts have said, I hooked up the furnace to the oil boiler as well. I set the cut-in/cut-out for the oil boiler below the wood boiler so it won't kick in unless I let the fire go out on the wood boiler. I installed a heat exchange between the wood boiler and the baseboard system because my wood boiler is about 20' lower than the house. The Heatmor furnace is an 'open' system (not-pressurized) and the water would have run out of the baseboards otherwise. If the furnace is sited at the same level as the house or higher, that would not be necessary.

As far as anti-freeze goes, I ran mine for five years or so without it. I added anti-freeze to the wood boiler system prior to shipping to Iraq because my family was going to heat with the oil furnace for the two winters I'd be gone. It's not a necessity though.


If anyone wants to see pictures of the setup and is willing to explain how to add them to a post, I'll be happy to include some. I'm extremely happy with the heat and the system I have and now wouldn't have a house in Maine without it.


P.S. If the power goes out the furnace doesn't work (as someone said) but that's true of indoor boilers as well (unless you have the fancy valve setups). I have a generator that I use with the power out...I like my conveniences, running water, hot showers, internet...

super
07-19-2009, 09:32 AM
I see where you can store your extra heat in a large tank, generally the tanks are over a 1000 gallons. This does allow a buffer between cycles and when you're not firing your unit.

firefighterjake
07-20-2009, 07:19 AM
Holy cow . . . this thread was dredged up from the past . . . all the way back from 2005.

super
07-20-2009, 07:32 AM
Sorry Jake, but I couldn't resist. I found your original thread lost out in cyberland and had to post. I enjoy talking shop so I hope you'll forgive me this time.

:)

firefighterjake
07-20-2009, 01:04 PM
No problem Super . . . as it was I ended up going the "easier" route and purchased a woodstove which I am quite happy with as it is providing plenty of heat through the whole house.

And now that you've found our site . . . don't be a stranger . . . feel free to post about any geocaching topics that might strike your facy . . . and yes, Springfield may be a bit of a drive from Maine, but you're more than welcome to stop by and visit our state on vacation any time.