Breaking Shear Pins on My DF 520

I Have an EFM DF 520 coal stoker boiler heating abouy 50% of my 10,000 sq ft 100 year old B&B in NW new Jersey. I was previously burning 3000 gals of oil per season, now I am using about 15 tons of coal/yr. I am very happy with my boiler but have resorted to burning buckwheat coal as my only supplier who delivers, only stocks that, no rice, unfortunately. I inted to build a larger bin and get 23 tons at a time by triaxle for next winter. In the meantime I am going thru 5 or more shear pins a week. I am assuming this is because of the size and hardness of the coal. Could there be another issue at play? Might I have compacted fines in the stoker tube worsenig this problem? I will make it thru the season but this is a nuisance as the system quits too often.
Could I upgrade the shear pin and what is the downside of that?
I am also making an auger type ash removal system with an 8 foot screw from Egan Co. and a small 60 rpm gear reduced electic motor..

Welcome to the forum!

Sounds like your auger may be worn, this causes the coal to be pulverized and jams up the works. Next time you get a chance inspect the auger for a knife edge (should be a square edge on the outer part of the helix), if it has this time to weld a new edge or replace.

Hello GlenLake, welcome to the forum

We all would like to see that ash removing auger setup when you have it up and running!!

Hopefully Stoker Man will chime in soon, he is our resident EFM service guy.

I would suggest removing the auger if yuu can and inspect it for rounded and worn flights that could cause binding...

I would not recommend changing to a stiffer shear pin, they are breaking ot prevent the breakage of other, more expensive parts...

So, when a shear pin shears, what is your proceedure to clear the auger, and clear whatever has jammed the feed?? Have you found any rocks or chunks of wood in the auger causeing a jam??

I think Lincolnmania has an EFM furnace that he burns buckwheat in, and I've heard that many folks do burn buck instead of rice... so I suspect you have something worn causing the jams...

Take care, Greg L

My manager whom is running the unit says he thinks the ratchet pawl is slipping so I have ordered a replacement and will swap it out ASAP. We have found a few rocks. Generally when this happens I tell him to crank the coal through by hand to feed up any problems. I am in Florida so I need a remote surveillance capability. I have purchased for $400 an ATT 2 camera video Internet system that also includes a temp sensor and a door sensor. I am also thinking of integrating a carbon monoxide sensor that will kick on an exhaust fan when CO rises. My fire alarm system in my B&B has 4 CO sensors that have gone off with outfires. I can sit at the beach and watch my Boiler over the net....

What a life,,, I'm jealous... BTW, I have two remote cameras, they are pretty nice to have..

Greg L

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Hi Doc, Are the two pipes tight against each other inside the pipe couping? Is your worm inside the coal bin (protruding from the pipe) no longer than 3 inches? Buckwheat may cause some pin breakage but not at the rate you are experiencing. I don't suspect the worm because the unit is fairly new. I don't suspect the drive pawl either. It should last 3 lifetimes.

There was one man who constantly broke shear pins and we went over the possible causes, but I just can't remember what it was. It was definitely related to the pipes or worms. I might have to give him a call. Once we figured out the problem, he stopped breaking pins.

puts flame suit on.........finishing nails do not break like those crappy shear pins

No flame suit needed. We like to sell replacement worms

That's OK scott, if you break your stoker gearbox, or twist a worm in two, you won't have to come home from the florida beaches to the frozen north to fix the problem... If your EFM shuts down, you will just have a few frozen fords..

Greg L.

true......the efm has been down before and we just fired up the warm morning and I put a box fan in the doorway to my room and pumped heat out of my room......as long as I can keep the garage above 50 I was fine........i think my problem was oversized buckwheat coal.....the stuff from hegins is alot bigger than the stuff from superior....the hegins coal I would have some pieces up to 2" long

I know it's tough from the beach, but the way to solve this problem is to shut down and take a close look at the auger. Something has to be bent/broken/jammed to break that many shear pins. Maybe have the attendant take the coupler off and see if the pipe is packed full of fines or if there is an inner tube or something jammed in there.

Thanks for all the comments... I had my mgr bang on the feed pipe and then unscrew the coupler. He claims he found several small diamonds and a large compressed piece of charcoal briquette. He removed them and cranked it thru. Says it hand cranks easier now... I guess there was a gap in there compacting fines...Hence the Diamonds... We know where to look next time..Thanks The moral may be you can burn buckwheat in an EFM.. We will see...

Another suggestion is that wet coal will also cause compaction and problems. Can you send me the diamonds; I have an anniversary coming up.

We are having major issues with our EFM 520, everytime we start a fire in the stoker & it starts to feed the coal the sheer pins snap. It has been 2 wks with no heat and its pretty cold in our house we had a friend of a friend look at it & he said the burn plates are shot. We have 2 electric fireplaces & 2 electric heaters but its not enough we need heat. Can anyone help? My bf said when he the coals starts to feed it jams up & breaks the pins. Not sure if the burn plates is the only problem if there is another problem we are not aware of. He cleaned the whole furnace out and removed coal dirt & any chunks of ash and or rocks that may have been jamming it up, PLEASE HELP!

Have you cleaned the feed tube or taken it apart to see if that's where the clog is.Someone with your boiler will help you with finding the solution.And welcome,you came to the right place for help