Can I Replace My Outdoor Wood Stove With a Coal Boiler?

I purchased a Harman insert last week to heat my basement and now I am interested in replacing my outdoor woodboiler (OWB) with a self feeding coal boiler if possible.

My current set up is as follows:

-OWB set up to run wood only is around 75' from my house (First photo)
-The heated water is transfered to my house and returned to the OWB via two underground 1" pex tubing
-Heated water is run through a heat exhanger located in my forced hot air system (Third photo)
-Stand alone 110 thermostat that turns on the fan only in my propane heater when the thermmostat calls for heat (Second photo bottom stat)

My current wood consumption is +-10 cords per year

I have an unlimited supply of free firewood but a limited supply of energy and time

Can I use my existing system and replace my current wood boiler with a coal boiler?

Edit: Adding a boiler in the basement is not an option. Basement is finished and the existing chimney is stone

Changing to a coal boiler is by far the best option you could chose to replace your wood boiler. A good chimney, lines in the ground, you are all set. My setup is just like yours. It looks like you have heat loss with your underground. How did you install it?

stokerscot wrote:Changing to a coal boiler is by far the best option you could chose to replace your wood boiler. A good chimney, lines in the ground, you are all set. My setup is just like yours. It looks like you have heat loss with your underground. How did you install it?

Yes I have some heat loss. Four degrees to be exact.

The piping is only buried around 20" due to the high water table.

When I installed the piping I used a layer of 3/4" stone as a base, filter fabric, sand the 1" pex tubing sandwiched between 6" of round insulation with cut outs for the tubing supplied by the mfg and then another layer of sand.

What coal boiler are you using?

I use an EFM 520. They work unbelieveably well for this kind of install. Mess stays outside. Extra heat for the garage. You can build a large bin and ash removal system and ,,,, well ,,, the possibilities are endless. 4 degrees loss seems like a bigger number. Guess if it's laying in water that number isn't too bad.

Have a look at my thread:EFM = Electric Fireman (New Project Alert). I just put a match to my "outdoor" boiler yesterday and it's working fabulously. My project was a lot more than just a boiler install, though. However, I can already tell you that it's a lot nicer carrying a 5 gal bucket of coal 25 feet from the coal pile around back of the garage compared to carrying 50lb. bags of dripping rice coal through the laundry room, kitchen, down the finished stairs and across the finished basement to the Keystoker. When the price of Blaschak bags hit $375/ton out here and natural gas hit $.43/therm I decided as much as I love coal burning, I can't justify throwing money away to the trucking companies and got real busy on getting my install done. Now I burn Illinois coal at $80/ton (not figuring in my own "trucking" cost).

First glance it appears this would be a simple out and in

but I have tripped on myself before

Keep reading here - lots of good information to help you smtm

You may want to consider an upgrade to modern energy transmission lines and unharness your self from that ground loss load.

stokerscot wrote:I use an EFM 520. They work unbelieveably well for this kind of install. Mess stays outside. Extra heat for the garage. You can build a large bin and ash removal system and ,,,, well ,,, the possibilities are endless. 4 degrees loss seems like a bigger number. Guess if it's laying in water that number isn't too bad.

Thanks for the info.

The stove sits outside the garage (its actually a wood shop ) and is heated with a radiant heat system installed in the concrete floor. I guess I will have to insulate the boiler

The temp loss was measured at the stove with a thermal thermometer. I think it looks like more but that is also the shortest path back to the shop to feed the fire and feed the chickens.

Coming in late here, but I saw/helped a guy use water line heater strips on water lines that were only 24" below the surface.....you may be able to do that to help with heat retention...all insulation does is slow heat transfer.....the water in the pipe will continue to drop temp unless you get below frost line (which doesnt look like an option for you) OR use some sort heat strip on the pipe meant for underground apps...I would still switch to coal either way.....I did and havent looked back! I am heating my 2400 sq with my Hitzer coal stoker (using about 30 lbs a day) when I had wood I was using 6-7 cords to get same heat...my wood was free also, but my time wasnt and it was limited as well. So far this yr I have used about 1200 lbs of coal since I lit in October. I keep my house at 72 days and 75 at night (2 young girls that get cold).

So that's not a big swath of thawed ground Ooops, sorry. My eyes are getting fuzzy by Sunday morning Is the outdoor boiler indoors? Or just past the garage?

stokerscot wrote:So that's not a big swath of thawed ground Ooops, sorry. My eyes are getting fuzzy by Sunday morning Is the outdoor boiler indoors? Or just past the garage?

The bare ground that you see right by the building is thawed ground out. The rest is just a path worn out by the many trips to load the beast.

The boiler is both outside and inside

You are going to want to close it in if the coal boiler is in your plans. They work better closed in. Does your unit burn coal?

Several forum members have exactly what you are describing..

I agree that you will be happier with the boiler enclosed, at least to keep the snow off the floor around the boiler, and snow/ice out of the coal..

I installed an Axeman Anderson 260 in my outdoor boiler room, I have insulated, burried pex-al-pex pipes 150' to the house, I'm using water-to-water heat exchangers to transfer the heat to the house's hydronic heat system, both baseboard and infloor heat.

I also have another pair of pipes going to my 40x60' shop to heat the concrete slab.

I fill my hopper every week or so, depends on the weather, and empty an ashpan every 2 -4 days, depending on coal quality and coal use rate..
It's MUCH easier than feeding the wood-eater OWB's..

Greg L

stokerscot wrote:You are going to want to close it in if the coal boiler is in your plans. They work better closed in. Does your unit burn coal?

I have tried to burn coal in my existing OWB without much luck.

The coal ash ends up putting out the fire and I have not been able to design a system that will effectivly shake out the ash.

Yeah, if they're not designed for coal, it's just easier to get a coal boiler. Have you been looking?

stokerscot wrote:Yeah, if they're not designed for coal, it's just easier to get a coal boiler. Have you been looking?

Just started looking for a boiler...today