Uneven Coal Burn in an EFM 520

Stoker Coal Boilers automatically feed the coal and have controls and pumps just like any conventions boiler. They are intended to be used as a primary heat and often have domestic hot water coils as an added bonus. They can be set up independently or in dual sytem with your existing oil/gas boiler. They can accommodate both hot water base board or steam plumbing.
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winter clove inn
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Posts: 7
Joined: Sun. Dec. 26, 2010 8:39 pm
Stove/Furnace Make: efm
Stove/Furnace Model: 520

Post Sun. Dec. 26, 2010 8:55 pm

I recently fired my EFM 520, it burns great for up to 12 hours. Then I notice the dark coal in the center starts expanding toward one side.About a 3'' wide strip of unburned coal reaches the edge and falls into the ashpit.I am running 6 teeth on the coal feed and between 5 and 6 on the air.
thanks in advance for your help, Bud

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Joined: Sun. Jan. 10, 2010 12:22 am
Stoker Coal Boiler: Kewanee boiler with Anchor stoker
Coal Size/Type: Chestnut / Sub-bituminous C
Other Heating: Propane wall furnace back up only
Location: Cantwell Alaska

Post Sun. Dec. 26, 2010 9:21 pm

You might repost this in the manufacturers forum. But I'm sure answers will flow here, since you have fuel and heat I would guess it's an air problem, maybe the holes in the tulip that the coal and air mix in are pluged, EFM also seams to have a rod or lever for droping the ash out from the chamber below the grate or tulip.

Problem area might be visible in this link
Pictorial: the Burner Pot Assembly W/Part Numbers
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Rob R.
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Stoker Coal Boiler: EFM DF520
Hand Fed Coal Stove: Hitzer 50-93
Coal Size/Type: Lehigh Rice
Other Heating: Dad's 1953 EFM Highboy
Location: Chazy, NY

Post Sun. Dec. 26, 2010 9:28 pm

Hi Bud, is this the first time you have used this unit? Sounds like a worn auger and/or a burner plate issue. I would start by shutting it down, and cleaning out the pot. Then you can inspect the different components. Check the auger for sharp edges, try and move it around to see how much play there is, make sure the burner plates are intact, and that the airflow isn't blocked with fines.


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Stoker Coal Boiler: 1959 EFM 350
Hand Fed Coal Stove: Harman Magnafire Mark I
Baseburners & Antiques: Sears Signal Oak 15 & Andes Kitchen Range
Coal Size/Type: Rice and Chestnut
Other Heating: Fisher Fireplace Insert
Location: Stillwater, New Jersey

Post Sun. Dec. 26, 2010 9:32 pm

Moved topic to the EFM forum.
Check for clogged holes or a damaged grate section or two. Did you pull the fines lever? Did it make a difference?
Heating a circa 1832 farmhouse with a Harman Magnafire Mark I & a 1959 EFM 350 (heating DHW).
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Hand Fed Coal Boiler: 1981 efm wcb-24 in use 365 days a year
Coal Size/Type: Anthracite/Chestnut
Other Heating: Hearthstone wood stove
Location: Lehigh Valley, PA

Post Sun. Dec. 26, 2010 10:01 pm

I'm with these guys. It's something wrong with the burner plate itself or a fines build-up underneath and possibly the worm, but not likely.

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