Looking for an Outdoor Coal Stoker

I'm new to this and looking for two outdoor coal stokers, one for my home and the other for a cottage. Any ideas on where to find them, how much they cost, etc. The cottage has no heat now other than a huge fireplace. I would like to retro fit it with under floor hot water heat. Its about 1100 sq ft built in 1933. My home is about 1500sq ft and has oil forced air. Are there any outdoor coal stokers for hot air? Has anyone used underfloor hot water heat and if so how does it compare to baseboard or hot air? Any info would come in handy. Thanks John

Hello and welcome.

there are no outdoor coal stoker boilers or furnaces that are designed to stand alone outdoors like an outdoor wood boiler.

What many of us do, including myself is to build a small insulated building to hold a regular indoor stoker BOILER and a supply of coal inside.

Then use good insulated pex-al-pex tubing to run the hot water into the house. \

For a hot air system, use a water t0 air heat exchanger in the furnace ductwork [on top of the existing furnace] to provide hot air.

Start reading, and read and read some more, there are dozens of threads on the forum about the same subject.

Greg L

Hi John - Do you intend to burn anthracite or bituminous coal? I have seen an outdoor coal boiler called the "Coalman", but it is intended to burn bituminous (soft coal) only, and is quite expensive...(probably way oversized for your 1500 sq. ft home).

Like Greg said, lots of guys put tradiational stoker boilers in outbuildings and run underground lines to the house.

john17751 wrote:Has anyone used underfloor hot water heat and if so how does it compare to baseboard or hot air?

Radiant heat is very even, vern comfortable, and doesn't require blowing air around. It is probably the most expensive way to go, but the end product has no equal. Do you intend to do some sort of "warm board" install over your existing floors?

It is important that you do a heat-load calculation on the structure; if it is poorly insulated and drafty you will may have to tighten it up to avoid high temperatures in the radiant floor.

LsFarm wrote:Hello and welcome.
What many of us do, including myself is to build a small insulated building to hold a regular indoor stoker BOILER and a supply of coal inside.

Hi Greg..Just wondering..why did you choose to do that? ..Build an outdoor enclosure? (from reading these posts, I get the impression that you have plenty of elbow room, and space to place a stoker indoors some where).

I have 2 boilers in my garage and hate that it takes up the space that it does..I actually wish they were in tha basement so I could benefit by geeting the radiant heat within the homes' living space..

Hi everyone and thanks for the info so far. Greg, after reading from this forum, I see that putting a stoker in an out building is the way to go. Gives you more of a choice in hot water stokers. How big should the building be?

Rob, I plan on burning anthracite. The cottage on the 1st floor has open 16" on center floor joise's over an open crawl space with no insulation, so I was thinking of putting the tubing with aluminum heat plates under the floor along with reflective and reg. insulation. I will need to check on the heat load. As of now I have renovated two of the three existing rooms and added insulation and the new addition will be insulated. It was very drafty.

Also, I have read that using either a coal or wood boiler that the water is to hot for radiant floor heat and that you need to add a mixing valve. I was planning on using antifreeze in the system in case of power outages as well as it being a seasonal structure. Will the mixing valve dilute the antifreeze over time? Any ideas?

Thanks again.

john17751 wrote:Also, I have read that using either a coal or wood boiler that the water is to hot for radiant floor heat and that you need to add a mixing valve. I was planning on using antifreeze in the system in case of power outages as well as it being a seasonal structure. Will the mixing valve dilute the antifreeze over time? Any ideas?

It is good that you are doing some reading and educating yourself before starting the project. You are correct that the boiler water will need to be tempered for use in the radiant zone. The mixing valve won't be a problem with antifreeze, just make sure the valve itself is rated for use with glycol.

Will the mixing valve dilute the antifreeze over time?

The mixing valve only adds cooler system return water to the hotter system supply water to temper it down to the desired temperature...it is all the same glycol mix...nothing added to system to dilute the antifreeze down.

Thanks Rob and McGiever, A house I had in the past had a oil hot water boiler and every once in a while it would add water to the system automatic. Not sure why so thats why I was asking about dilution. I assume the oil boiler must have been an open system (?) and the new system should be a closed system?

Any sugestions on a boilers. I would like one that has a hopper or system that could run a few days to a week without filling. How often do you need to empty the ash pans. How many tons of coal do you use and what sq ft are you heating. I live in central Pa, Williamsport/State College area

I'm so glad I found this forum. Everyone has been very helpful.

john17751 wrote:A house I had in the past had a oil hot water boiler and every once in a while it would add water to the system automatic. Not sure why so thats why I was asking about dilution.

The system probably had a leak. In a "closed" hydronic system with no leaks, you shouldn't have to add any water.

john17751 wrote:Any sugestions on a boilers. I would like one that has a hopper or system that could run a few days to a week without filling.

When it comes to stokers they are either hopper fed, or auger fed. An aftermarket auger can also be used to fill the hopper units, but naturally that increases the price and complexity of the system. Do you want to go a week without filling just for convenience? -or are you going to leave the boiler for a week at a time? In my opinion, solid fuel boilers are a good choice for someone that is home everyday...and a poor one for someone that travels. You can design the system to accommodate your schedule, but it will be a lot more complicated and probably require an ash removal system.

john17751 wrote:How often do you need to empty the ash pans.

I don't mean to sound like a wise-guy, but "it depends" on how much coal you burn, the ash content, and the size of your ash pan. On the coldest days of the year my EFM will fill (or slightly overfill) a 1-bushel ash tub in 24 hours. That works out to 140-150 lbs of coal burned.

john17751 wrote:How many tons of coal do you use and what sq ft are you heating.

Again, the answer is "it depends". I burn 8-9 tons per year heating 3500 sq. ft in the Northeast corner of New York State. We also product domestic hot water with the boiler. You might not burn even half that much, but it all depends on how well the structure retains heat and how much hot water you use (assuming you produce hot water with the boiler).

Edit: Does your house have a basement?

Rob R. wrote:I don't mean to sound like a wise-guy, but "it depends"

or

"Let me get back to you on that"

Rob, The cottage is only 1/2 mile from my home and I usally go there every other day at least, so I would say filling the hopper would be for convenience. I don't want a complex system. When I'm not there I would set the temp to 55 or 60 degrees to keep the domestic water from freezing. I will be using antifreeze in the hot water heating system. We do spend the weekends there. It has no basement, only an open crawl space. I will do almost anything to get away from buying oil and start to use a domestic heat source.

I see you have a efm520. Do they make a smaller BTU stoker. I've been to their web page and all I see is the 520. I'm just guessing but would say the biggest I would need for 1100 sq ft would be 200,000 BTU +/- ? I still need to do a heat loss for the structure.

john17751 wrote:I still need to do a heat loss for the structure.

Yes you do.

john17751 wrote:I'm just guessing but would say the biggest I would need for 1100 sq ft would be 200,000 BTU +/- ?

Unless the cottage is missing the North wall, it shouldn't require anywhere near that many btu's. You wouldn't be able to put that much heat through the floor anyway.

john17751 wrote:I see you have a efm520. Do they make a smaller BTU stoker.

They used to make a 350 model, but it can't be fired at any lower of a BTU output level than a 520...the boiler itself is just smaller. Either one would probably be fine for your application.

What drove you to install radiant heat in the "weekend getaway" cottage in the first place? Sick of cold floors?

Lol,I still have the north wall. I did 2 heat loss calculations from 2 different web sites and they both came back at around 70,000 BTU which surprised me. I thought it would be much higher. Thats why I'm glad I came to this forum. As for the radiant floor heat, I haven't done that yet. It just sounds like it would be better use of heat, warmer floors, etc.

Hi John Leisure line makes a small 'baby boiler' that comes with a backup oil gun so you can use oil if you are going away for awhile and could not use coal in the boiler. You may be able to do the same with your existing oil systems.

My boiler building was an old, existing stone outbuilding with a collapse roof, I resurected it by putting a new roof on it many years ago, but then decided to use it as a remote boiler building. This building is roughly 13'x20'.

For me, with the large amount of coal burnt and large amount of coal ash generated, I didn't want the boiler in the basement, the logistics of getting coal into a basement, even with a coal chute and coal bin, were daunting, and then the hauling of coal ash bins up basement stairs was more daunting..

AND couple the above thoughts with the desire to also heat by coal, my large workshop which is 280' from the house. The location of the exixting building with a restored roof that was 1/2 way between the two buiildings, well it worked out pretty good.

Also when I installed the coal stoker, the house only had a rudamentary 'cellar' with limited ceiling height, and poor stairs for access.
But since my "HUGE Project' house partial demo and rebuild, I have a wonderful basement and would consider a small LL110 boiler in the basement and a similar one on the shop,,, maybe.. It would still not be as nice logisticly, to keep the work and coal and ashes outside.

I had radiant hot water floor heat in the new section of the house, and in the entire floor of the work shop [40'x60']
To be Blunt and an evagelistic, and probably even a Zelot...

I WOULD NEVER BUILD A HOUSE WITHOUT RADIANT FLOOR HEAT IN OUR CLIMATE

The comfort is just hard to describe,, it does cost a bit more than conventional forced hot air [aka Scorched Air] or hot water baseboard, but like I screamed above, I'd never do without it again by choise.

As for other boilers and logistics, there are two stoker boilers that I like and recommend that have an almost unlimited size coal hopper, those are
the Axeman Anderson boilers, 130btu and 260btu, and the EFM boilers. Both of these boilers could have a whole winter season sized coal hopper built into the coal building as part of your built to design coal boiler building.

There are many other boilers that will go 2-4 days on a load, and these other stoker boilers come in various BTU outputs, configureations etc. [ I see MORE reading in your future !! ]

OK, my fingers need a rest.

Greg L

Greg, I also want to keep everything out side and hearing someone say they would never do anything other than radiant floor heat makes me feel like I'm on the right track. Since there isn't any heat in the cottage now, I feel I might as well do it right the first time. I would need to build a small building though to put the boiler and coal bin in as well. Sounds like we both take on big projects. Just to get to the cottage I bought in 2003 and hadn't been used in 15 or 20 yrs, I had to build a 180' suspension bridge from scratch (origanal one built in 1935 got washed out in 1972 flood) which took me a while to do.

Does anyone have any experience with the coal gun made by Alternate Heating Systems. Info looks interesting.