Boiler or Stoker Stove?

Boiler or Stoker Stove?

PostBy: Mike Wilson On: Sun. Mar. 30, 2008 9:00 am


I'm looking for some input here, any advice is welcome. Here's what I have, and what I'm thinking of:

Home is 3200sq/ft, contemporary, with very high ceilings (34' peaks, 29' peaks, 19' peaks, indoors). The house has 3 zone heating, and the design of the house is such that there is really no natural circulation between the zones themselves. The main zone is about 1700sq/ft, heating the living room, dining, kitchen, separate kitchen dining area, small bathroom, and an atrium with a 34' ceiling. Build is 15 years old, well insulated, all Andersen casements, wrapped, with a clear cedar TIG exterior, however it is in a very, very high wind area. We are 100' up on a bluff, with the house located 200' back from the water. 30 knot northerly winds sustained for 3-4 days are not uncommon, and suck the heat out of anything. Current heat source is an oil boiler that circulates water into the three zones. Each zone has an air handler with a heat exchanger in it, (and an a/c coil), where the water heat is converted to hot air, humidified for comfort, and dispersed in the zone. For the past 4 years I have also had a Jotul wood insert in my fireplace, and burn about 3 cord per year. If left to its own devices, with my southern California born and raised wife (who likes everything warm warm warm) and without the Jotul running, I burn 500 gallons of oil per month. With the Jotul it is 200-250/month.

Last year I did some research, and thought I settled on a Keystoker 90 in the basement, with a closed air loop, intake on one side of the main zone, output on the other side of the zone. I still think this will work well, and I have an (almost) local Keystoker dealer here. BUT, after reading all your recent posts on Boilers, I thought, what about something along the lines of a Keystoker KAA2 (or larger?) boiler plumbed into the boiler? Some restrictions HAVE to be adhered to though... It must be direct/power vented, and it must be in the basement. On another note, the existing boiler is most likely being replaced with a Buderus boiler and a Riello burner this summer. I don't like the idea of 4.00 oil.

Any opinions or comments would be welcomed.

Last edited by Mike Wilson on Sun. Mar. 30, 2008 9:23 am, edited 2 times in total.
Mike Wilson
Stove/Furnace Make: Keystoker 90 DV
Stove/Furnace Model: Jøtul Kennebec Wood Insert

Re: Boiler or Stoker Stove?

PostBy: 1975gt750 On: Sun. Mar. 30, 2008 9:07 am

hey mike I would definatenly go with a boiler I have a kaa-2 here at my house and works great and I am heating 2000 square feet.if I was you I would use a ka-6 I think the kaa-2 will be two small for your heating situation. if you have any questions feel free to contact me and I have plenty of pics. I used to live in lake ronkonkoma and now live in new hampshire and you are right the the oil prices are out of contoll. I used to burn 600 gallons a year now I burn 3 tons of coal.

Stoker Coal Boiler: keystoker kaa-2
Coal Size/Type: rice coal / blaschak
Other Heating: pensotti oil boiler with riello 40 burner
Stove/Furnace Make: keystoker
Stove/Furnace Model: kaa-2

Re: Boiler or Stoker Stove?

PostBy: coalkirk On: Sun. Mar. 30, 2008 9:09 am

I'm not real familiar with keystoker boilers but if you are supplying 3 water to air heat exchangers, I don't think that boiler is going to be large enough. Direct venting is going to be the biggest obstacle. How is your oil boiler vented? It sounds to me from the desription of your home and present system, a coal boiler would be ideal. Most need a class a chimney though. If your oil boiler is vented into a class a chimney, I would consider using that chimney for the coal boiler and direct venting the oil boiler. By the way, with a properly sized coal boiler, you would not burn any oil. i'm heat 4,000 sq. ft with my boiler and 1 water to air exchanger and did not have to fire my oil boiler at all this season.
Stoker Coal Boiler: 1981 EFM DF520
Coal Size/Type: anthracite/rice coal

Re: Boiler or Stoker Stove?

PostBy: jpen1 On: Sun. Mar. 30, 2008 9:28 am

How many btu' is your current boiler/furnace rated for? The Keystoker 90 would be way to small for that type of heat loss. Maybe the keystoker koker ( is direct vent cabable) would come close but your best bet is a boiler like the keystoker KA-6, KB-8 or an EFM 520 . However all these boliers require a chimney and if your oil boiler/furnace is vented into a chimney you are better off powerventing the oil appliance especially if you are putting a new one in, especially sine the power vent is half the price for oil appiances and should last longer and be less maintanence. However you could just get the coal boiler and do away with the oil all together :D .
Stoker Coal Boiler: LL110
Coal Size/Type: Rice/ Buck
Stove/Furnace Make: Leisure Line
Stove/Furnace Model: 110 Boiler

Re: Boiler or Stoker Stove?

PostBy: Mike Wilson On: Sun. Mar. 30, 2008 9:42 am

Let me just add that the Keystoker 90 idea was to simply heat the main zone, not the whole house. The Jotul now effectively heats that zone, and its manufacturer's rating is 55K BTUs. Taking that heat load off the oil boiler was enough to make me happy! Also, I like the idea of direct venting the Buderus and using the existing chimney for the coal boiler. It's an 8" flue, I think, last time I measured. I do, however, have the wind problem to deal with, and there is no way the wife will stand for coal smell coming back into the house... that would break the deal!
Also, from memory (without pulling files on a Sunday morning), the existing boiler is a Weil McLain 466 boiler. My oil burner guy said it is about 165K BTUs gross, around 130-140 BTUs output net.

-- MW
Mike Wilson
Stove/Furnace Make: Keystoker 90 DV
Stove/Furnace Model: Jøtul Kennebec Wood Insert

Re: Boiler or Stoker Stove?

PostBy: LsFarm On: Sun. Mar. 30, 2008 1:11 pm

Hello Mike, there is not any smell from burning Anthracite coal. I can intentionally walk all around my boiler building and not notice any smells.. Bituminous coal is a different animal, it has more sulphur and soot... But you won't be burning Bitum. coal... Anthracite burns with a clear blue-white flame, no smoke, or soot.. just some dust called fly ash.

I would certainly go with the boiler...I wouldn't consider the supplemental space heater... it would probably do as you describe, take the BTU load off the main zone.. but why since you will be loading coal, removing ash, procuring coal, etc... why not heat the whole house with this economical, clean fuel?? The added costs of adding on a coal boiler instead of a supplemental heater are not all that much..

I will make another suggestion: with those very high ceilings... have you considered heating the floors with hydronic floor heating??? Keeping a floor surface warm will provide much more 'creature comfort' than hot air that is rising to the peaks.. If the floor is warm, the creatures are warm,, and the air in the peaks is not at 95-100*.. just something to think about.. Most new-construction homes of your design use hydronic hot floor heat, and ductwork for A/C.

I would HIGHLY recommend the coal boiler.. you should get at least a KA6 or an EFM 520, or an AHS130-260 or AA130-260.

Greg L
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland

Re: Boiler or Stoker Stove?

PostBy: gaw On: Sun. Mar. 30, 2008 7:11 pm

If you make the decision to go with coal, and are sure thats what you want to do then I would install a coal boiler. A few years ago I was considering a Buderus with the computerized controller and all the bells and whistles to lower my oil consumption. In the end I went with coal and made a 100% commitment to it. I completely removed the old oil boiler and installed a coal boiler in its place. In hindsight it is the best thing I ever done. If I were you I would take the money you are considering for a new Buderus and buy a coal boiler. You could keep the old Weil McLain as a backup if needed.
Stoker Coal Boiler: Keystoker KA-6
Coal Size/Type: Rice from Schuylkill County

Re: Boiler or Stoker Stove?

PostBy: Yanche On: Sun. Mar. 30, 2008 9:34 pm

I'd buy an Anthracite coal fired stoker boiler. Use your existing oil boiler as a back-up. Since it would now be a back-up I'd reduce the oil nozzle size. This would make it more efficient at the expense of reducing maximum BTU output. A good trade off in a back-up unit. Be sure to understand the demands of coal and ash handling. With all those strong winds I'd also look into wind driven alternators. Might as well harvest some of the "free energy".
Stoker Coal Boiler: Alternate Heating Systems S-130
Coal Size/Type: Anthracite Pea

Re: Boiler or Stoker Stove?

PostBy: katman On: Mon. Mar. 31, 2008 9:40 am

Sounds like your house design is like mine, only a little bigger, and the spouse has similar attitude to mine, who grew up on the eastern shore of Md and llikes things warm and natural.

Just got my normal spring oil delivery, so for the March 2007-2008 period I burned about 1200 gallons. The current price cap is $3.59.

My wife had the same issue with coal: smell and smoke. So, this winter I picked up a small Alaska stoker and put it in my barn/worksop, which previously was heated with a soapstone wood stove. That old wood stove put out a lot of smoke. The coal stove kept the place warmer, required less work, had no smell and was smoke free. This little demonstration/test convinced the wife. I plan to put a coal boiler in the barn before next winter and run an underground line to the house, using the oil boiler as a back up.
Hot Air Coal Stoker Stove: Harman Magnum
Other Heating: Harman PB 105 Pellet Boiler

Re: Boiler or Stoker Stove?

PostBy: Mike Wilson On: Wed. Apr. 02, 2008 7:52 am

Okay, I'll go to my dealer and see what information he has on boilers, what manufacturers he deals with, etc. It does make sense that if I go to coal as a primary source, I should just keep the oil boiler I have now as a backup/supplement. Then the issue becomes venting the coal boiler. Currently the oil burner is in the flue, and I'd probably keep it that way, so I'm going to have to look at power venting options for the coal stoker. (Unless anyone here knows whether you can simply add on a power vent to a Weil McLain boiler...???)

-- Mike
Mike Wilson
Stove/Furnace Make: Keystoker 90 DV
Stove/Furnace Model: Jøtul Kennebec Wood Insert

Re: Boiler or Stoker Stove?

PostBy: Sting On: Wed. Apr. 02, 2008 8:20 am

May I suggest you contact the folks at Weil McLain boiler and get their recommendation for PV. Failing that, I would contact customer service at TJERNLUND and get their recommendation for a PV on the gas / oil boiler.

And put the coal boiler on the stack after you have it inspected by a certifies chimney sweep.

Now as to what to buy - you want something that is big enough but not too big. The only way to ascertain the correct size coal boiler is not by recommendation of a salesman, but by a careful heat loss calculation of your load. Then figure a (30% ???) indecency loss from input to actual out put and buy an appliance that fits that target.

Here is a good set system heat loss calculator and its free.

Down load the Heat loss software and post your results please!
Other Heating: OBSO Lennox Pulse "Air Scorcher" burning NG

Re: Boiler or Stoker Stove?

PostBy: Charlie Z On: Wed. Apr. 02, 2008 8:22 am


I live down the Fork (in Orient a lot to race from OYC and I fly into rose occasionally, which is probably close).

Greg (LSFarm), Yanche and the 'big boiler' guys are right on this one, because of the size of the house and your enjoyment of the woodstove that you want to keep. AHS, AA, EFM, etc, plumbed into your central would be the way to go for a couple of reasons, primarily that you have a hard-to-heat house. It'll give you DHW, saving another $1300/year, too.

We've burned 25 gal/mo to heat our water and no oil for heat this year in a 1300' drafty frame (@ 75*) with a handfired. Drop in if you want to see it in action. (Looking to collect buyers to co-op bulk loads on the NF.)

- Charlie
Charlie Z
Stove/Furnace Make: Coalbrookdale
Stove/Furnace Model: Darby

Re: Boiler or Stoker Stove?

PostBy: Mike Wilson On: Fri. Apr. 04, 2008 4:28 pm

Hey Charlie, you have a PM!

-- Mike
Mike Wilson
Stove/Furnace Make: Keystoker 90 DV
Stove/Furnace Model: Jøtul Kennebec Wood Insert