Real Rating BTU

Yes, the draft must be definitely controlled or you will have an out-of-control fire, waste alot of coal, and lose alot of heat up the chimney.

Phil,
I have the woc55 the next size smaller than yours,with the oil gun.My house is simular in size,practicully no insulation except the ceilings,but somewhat air tight.I live in the Phila./Reading Pa. region,not much wind and warmer than where you live.I'm heating only my house right now with 50/60 lbs. UAE nut a day,1 person showering and dishes,70 degrees in house with 25 to 50 degree days. It seems you should be getting much more heat from your boiler.What are your stack temps. and do you have a baro installed.Do you use the bottom combustion blower.I modified the combustion blower draft and installed a air dam below the grates to dirvert the air directly into the bottom of the coal bed. With 50 % of the firebox reduced approx.80 lbs coal and a 13" firebed it only take 15 minutes for the temps to recover from 160 to 170 degrees, then temps. continue to rise to 180 degrees and recover with the entire bed of coals glowing orange,before the modification it took 30 to 40 mins. to recover with only half the coal bed glowing.The air dam modification was the best improvement I done with the best succesfull effeciency. Contact me for the info. Dennis

I dont have a baro dampner. Which on warm days probably wastes some fuel. But it cant even begin to make enough heat on cold days. The difference from where you live to where I live is huge. My Mom and dad live in Ironton-coplay area near Allentown. Dad says Alaska is warmer than my place. I thought about mounting the blower on the side of the ash box with some diverters to fan the air out more. I dont use the blower currently just natural draft. If you know someone who wants a 70 let me know it is coming out next summer. A 520 or 700 is going in. Unless this so called coal shortage continues then maybe a woodchip burner or sawdust burner.

phil,
if you do have the blower under the grate on the side(like mine),there is no welding to the boiler.Just a few pieces of flat stock and a piece of all thread, maybe couple hours at the least to make.If you can take a few pics. of the blower and bottom of the boiler to see if both ours are simmular would be great. Dennis

Edit:
Phil you need a baro to keep your heat in the boiler instead of your chinmey.AHS recomends .04 although I have mine set at .03.The manometer will help in adjusting your draft and also to know when you are loosing draft. You high chimney is sucking all your heat away. What size coal are you using?

Phil,
After reading your post I was having flashbacks of my last heating season. I just built a new 3200 sq ft shop with 8 " insulated slab with radiant pex,( 3) 12' X 12" insualated Garage doors and( 3 )steel man doors. The building is a well insulated all steel building and I have two large pumps feeding 245 feet of 1 " pex to my existing 119,000 Btu oil boiler with 5 zones. I am also heating my finished basement @ 70* and a 3 car attached garage that is kept at 50* . The house with the basement not including the garage is 3100 sq ft of living space. I also live on a very windy hill (The nickname is 1 Mile hill )with a elevation of 2300' .

I attempted to heat the space with a 200,000 BTU DS Machine boiler . The DS would heat the shop with wood if you overfired it loading every 3-4 hours with dry oak or kept it loaded to the hilt with a wheel barrow load of hard nut coal. Every time I would have the house on line calling for heat the pumps would suck all the heat out of the boiler and it would take a good 40 min. with no load to bring it back with coal. Burning wood you could make it happen if you were their to feed it all day.

I looked at the EFM and liked everything about it, but due to space in my boiler room I needed something with a hopper and chose the S260 AHS. I finished installing it over the holiday last week and have been heating my shop at 65* and my whole house at 70*. The nights have been in the low teens, with the days gettingin the 30* s so the coal consumption has been less than my Ds boiler heating both the house and the shop. Next week we have a cold spell coming in and I should be able to get a better idea of what the boiler will use on a really cold day and how it will perform on recovery. So far the boiler has been idling and not breaking a sweat with the heat load of both buildings. I have been in my shop and the boiler kicks on less to maintain temp than my oil boiler every would.

Mac

phil'
if you need help,maybe i can help you get more heat from your boiler.Let me know. Dennis

Dennis
That is almost identical to what I was thinking of. Mine had the blower on the ash door from factory. The blower quit so I took it off and covered the hole. Now I got a chain that opens the ash door from the draft on the firebox door. I am going to get a baro dampner and try it out. The only difference I was going to make with the blower was a diffuser to make the air spread more towards the back of the ash chamber.

Phil,
do you use wood most of the time and if so,many forum member say not to use a baro.But if you do use coal you could install a MPD then install the tee in the pipe and cap off when using wood and when using coal install the baro in the tee.The tee also makes it easier to clean the pipe without shutting down.When I first made my diffuser, i bent some alum. stock and vise griped it to the ash pan for 2 weeks and moving around to find the perfect spot then made it out of flat stock laying around here,when you do make the finished diffuser make sure your grates can rotate and can remove the ash pan.I have mine just laying under grates where the ash falls into the pan, there is some flat stock steel welded at about 45 degree angle to dirvert the ash into the pan, if you look at the pics. the diffuser lays in the 45 degree part and hangs there.
On another subject have you cleaned the brick baffle on the water tubes inside the fire box at top.
Are you burning bit. or ant. coal. When burning coal do you have the triangle grates flat,if you turn them just slightly open you will get more air flow thru the fire.Is you coal burning completly or getting unburnt pieces in your ash.
How many btu's do you think you are using right now or how much are you currently heating now.
I have played around with the natural draft with the chain to the ash door,it had a much slower recovery time but didn't push heat up the chimney with the blower.I will take the quicker recovery time,besides it wasn't much heat lost. Dennis

Phil,
wondering if you were able to keep heat in the boiler and house.

Phil May wrote:I got a chain that opens the ash door from the draft on the firebox door.

When you were using coal only.
Something I wan't to ask,while using the chain off the firebox door to the ash door is the over fire draft open.On my boiler when the linkage on the firebox door opens it also opens the overfire draft(alot) allowing more air to flow thru and carry your heat up the chimney.I completly disconnected the overfire linkage and wired it shut.Were you able to install a baro or MPD. Dennis

I have not put it in yet. I still have a lot of wood to burn up to make way for a new or used efm.

Rob R. wrote:Hi Phil, I also live in a very windy area, in the very Northeast corner of New York State. Infiltration losses from the wind are my biggest challenge, but I have significantly reduced the heat loss of my house by replacing the windows on the wall that gets the most wind, and caulking/sealing the rest of the house the best I could. I recommend that you do the same.

As for the boilers, you can reliably get 200,000 btu's out of a 520, but the stack temperature will be higher than if you did the same job with a 700. I got the 200k number by allowing 12,500 btu’s per lb for anthracite, 20 lbs per hour for the stoker in a 520, and 80% efficiency. Yes it is true that the stoker in a DF520 can burn 25 lbs per hour, but in my experience if the coal burns a little slower than average, it is tough to get a proper burn at that setting. I have no experience running a 700, so I don't know how well it would run at maximum feed.

One thing I do have firsthand experience with is installing an EFM 520 in a house that was previously heated with a 105k btu oil boiler. It is my dad’s house, and the oil boiler used to run about 15 hours per day when it was zero and the wind was roaring. The EFM has no problem holding the house at 72 degrees on 4 teeth of feed (50% output) in the same conditions, and it runs about the same amount per day. I could increase the feed rate so the stoker didn’t have to run as much, but a -20 day doesn’t happen often enough to justify changing the settings.

Enough about my projects…lets hear about yours. Where do you plan to install the stoker boiler? Do you use a lot of domestic hot water? Why do you say the AHS hand-fired boiler can’t keep up with your oil unit? Would you be willing to fire up the oil boiler to help shoulder the load on exceptionally cold days?

It will depend on the coal you are using to determined what the max btu out put is on any coal burning unit
coal that burns at 13.800 btu per lbs x 20 lbs per hr will be 276k btu per hr input output at 85% efficiency will be 234.600k per hr at 80% efficiency would be 220.800k per hr

At 25 lbs per hr with coal at 13.800 btu per lb will be 345k input out put at 85% 293.250k per hr at 80% output 276k btu per hr

The exhaust temp will be determined by the air setting on blower the higher the air setting the higher the exhaust temp will be be less air setting less exhaust temp .

By controlling the air setting you will control the stack along with a draft control device that is set up proper on the stack pipe

Remember not all Anthracite is the same some needs more air to burn complete other's need less air to burn up completely
and some has more btu per lb then others you got to know the specs of the coal you are using to know what the max btu output will be on any coal burning unit

At the risk of irritating both of you, I agree with coalberner that it depends on the coal, but I agree with Rob that a btu/lb value in the 12,000's probably is reasonable to use for figuring purposes. Some of the higher btu numbers for anthracite come from "dry basis" or (D.B.) analyses, but I think for this discussion some accounting has to be made for the moisture in the coal, which detracts somewhat from the energy produced by the combustion. For what it's worth, the highest # I've seen claimed by EFM for a DF520 is 214,690 btu/hr. I agree some people may do better than that under some circumstances, but I also agree that anyone who would need to run a 520 at or near its maximum output to satisfy their needs probably should consider a boiler with a larger heat exchange area (e.g., a Highboy or 700).

Mike

For most down and dirty BTU calculation purposes, I've settled on just assuming 10,000 BTU's of output per lb. for anthracite. 10,000 BTU's simultaneously accounts for the typical 4 - 6% water content of anthracite, and the overall efficiency of many coal burning stoves, furnaces, and boilers.

I've generally heard that the total BTU capacity figure for nominally 4 - 6% wet anthracite (the kind people in the real world use) resides somewhere near either side of 12,250 BTU's.

10,000/12,250 = 81.6% efficiency

So if your coal is of normal wetness, and your stove/furnace/boiler is in the range of 80% efficient, then 10,000 BTU's is just about what you will get from one pound of your anthracite. Using 10,000 BTU's per pound saves having to do a bunch of thinking and ciphering.

Pacowy wrote:At the risk of irritating both of you, I agree with coalberner that it depends on the coal, but I agree with Rob that a btu/lb value in the 12,000's probably is reasonable to use for figuring purposes. Some of the higher btu numbers for anthracite come from "dry basis" or (D.B.) analyses, but I think for this discussion some accounting has to be made for the moisture in the coal, which detracts somewhat from the energy produced by the combustion. For what it's worth, the highest # I've seen claimed by EFM for a DF520 is 214,690 btu/hr. I agree some people may do better than that under some circumstances, but I also agree that anyone who would need to run a 520 at or near its maximum output to satisfy their needs probably should consider a boiler with a larger heat exchange area (e.g., a Highboy or 700).

Mike

EFM has not tested any of the boilers since the 50 and 60"s those number in there Manuel has not changed since they where printed way back when the coal they tested at the time is the results they printed in the manuals I have ones from 50 60 s and 80's the numbers are the same except max feed rate the early pot S -20 stokers ran 1 to 8 teeth max 20 lbs per hr the newer S-20 run at 1 to 10 teeth max 25lbs per hr max air setting 1 to 9.5 older Manuel the new Manuel that you can down load from efm say 3 to 10 teeth air is the same 1 to 9.5 . S-15 stoker ran 1 to 6 teeth max feed rate 15lbs per hr same as the AF 150 hot air furnace

If a 520 can't heat what you want it to or you have to run it full bore then look for a 520 highboy more heating surface and water cap is 54 gal vs 40 gallons . cheaper for parts and simpler to use then S-30 stokers 30 lb max per hr 700 boiler 74 gal S-35 35 lbs per hr 900 boiler 94 gal or 1300 S-45 45 lbs per hr 120 gal boiler stokers and smaller in size