What causes an EFM520 to back burn.

 
k-2
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Post by k-2 » Tue. Mar. 13, 2018 5:34 pm

I know there are many EFM experts here so I need some advice on that stove. I have a friend who had his 520 back burn down low in the bell possible causing the worm to break and several grates to become unusable. Or I guess its possible that the worm broke first and THAT caused the fire to burn down deep into the bell damaging the grates. What are the main causes for this to occur. I'm asking because i dont know anything about this model stove so I cant give him any advice on it.
Thanks in advance


 
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Post by Rob R. » Tue. Mar. 13, 2018 5:50 pm

Plenty of people have sheared pins and had the fire down low in the pot without damaging anything. My guess is that your friend has been running the stoker at an incorrect feed/air setting for a long time, and the parts were damaged as a result.

I suppose it is possible that the parts were already at the end of their life and this event finished them off, but that seems unlikely.

 
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Post by windyhill4.2 » Tue. Mar. 13, 2018 5:53 pm

Too much air for the amount of coal pushing thru will cause the fire to burn down into the pot...

 
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Post by k-2 » Tue. Mar. 13, 2018 6:07 pm

He is convinced his tenant caused it by turning up the thermostat to 85 degrees. Then turning it back down. I'm convinced you cant cause a furnace to malfunction from the thermostat ,no matter how far or fast or how often you turn it up and down. But I cant seem to get that across, so I told him id ask the experts.

 
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Post by Rob R. » Tue. Mar. 13, 2018 6:10 pm

My EFM sometimes runs for hours nonstop and the grates still look like new. The thermostat setting is not the problem.

 
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Post by k-2 » Tue. Mar. 13, 2018 6:19 pm

What about possibly too much fine coal dirt building up in the worm, would that cause it to break?
He also said he was getting some unburned coal in the ash. I suspect if the air holes in the grates were blocked,that would explain that.

 
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Post by StokerDon » Tue. Mar. 13, 2018 6:26 pm

I totally agree with Rob and W.H. I don't think there is any way you can hurt one of these by turning it on and of or running it for hours at a time. That is what they are designed to do.

If you let the fire burn down in the pot too far (to much air) you can do damage though.
k-2 wrote:
Tue. Mar. 13, 2018 6:19 pm
What about possibly too much fine coal dirt building up in the worm, would that cause it to break?
He also said he was getting some unburned coal in the ash. I suspect if the air holes in the grates were blocked,that would explain that.
Sounds like it needed to be serviced. Did he at least pull the fines lever once in a while?

-Don


 
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Post by k-2 » Tue. Mar. 13, 2018 6:37 pm

StokerDon wrote:
Tue. Mar. 13, 2018 6:26 pm
I totally agree with Rob and W.H. I don't think there is any way you can hurt one of these by turning it on and of or running it for hours at a time. That is what they are designed to do.
-Don
Thats exactly what im trying to tell him , you cant damage this or any stoker from the thermostat. There are other reasons why this happened . I feel sorry for the poor tenant cause i know he is getting the blame ,which is why I'm trying to find the REAL cause.

 
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Post by k-2 » Tue. Mar. 13, 2018 6:37 pm

What is the service interval ?

 
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Post by Pacowy » Tue. Mar. 13, 2018 6:44 pm

I agree with too much air being the prime suspect, so I don't think it's a service interval issue as much as a nobody-paid-attention-to-the-settings issue. Running it a long time that way with a hot fire low in the pot could easily harm the plates and auger. Blocked airholes or fines in the air chamber can harm the upper sections of the grates, but generally should keep the fire away from the auger. I also agree that thermostat setting changes have 0 chance of harming a unit with proper settings and maintenance.

Mike

 
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Post by StokerDon » Tue. Mar. 13, 2018 6:47 pm

Basically, if you are getting a lot of fines and they are NOT coming in the coal supply, something is worn out. On an EFM, this is usually; pot bushing, auger bushing, auger or pipe. If one of these is worn out, it's time to have a look at the rest.

-Don

 
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Post by Pacowy » Tue. Mar. 13, 2018 7:02 pm

A lot of fines can also result from too much auger sticking out of the pipe (even if all components are otherwise in good condition), and fines buildup in the air chamber generally results from insufficient pulling of the fines lever. This didn't sound like a fines problem but the owner should be aware of these things.

Mike

 
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Post by k-2 » Tue. Mar. 13, 2018 7:16 pm

Just as I thought there are half a dozen possibilities for this, none of which have anything to do with the tenant turning the thermostat up and down.

 
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Post by k-2 » Wed. Mar. 14, 2018 3:43 pm

I found out he is running it with the Timer turned off, said you don't need it turned on in the winter,(which I don't believe) but I think that may be the whole reason the fire burned down into the pot , long warm spells with no coal feed. I think it s just a backwards way to save coal that's damaging to the stove.

 
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Post by windyhill4.2 » Wed. Mar. 14, 2018 4:03 pm

k-2 wrote:
Wed. Mar. 14, 2018 3:43 pm
I found out he is running it with the Timer turned off, said you don't need it turned on in the winter,(which I don't believe) but I think that may be the whole reason the fire burned down into the pot , long warm spells with no coal feed. I think it s just a backwards way to save coal that's damaging to the stove.
Those with more yrs of experience than i have with the 520 may say different, But lack of timer will cause outfires, not pot fires.

In order for the fire to burn DOWN into the pot....
1- feed is set too low for the air...
2- Air is set too high for the amount of feed.
3- Yes, both are the same issue...

4- I just wanted to repeat myself without using the same words & to totally clarify what i am saying. :)


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