Back of pot not burning

A friend of mine ask me a question and asked that I post it on here because of the great feedback. He has a efm520 similar to mine but the back of his pot is not burning like the front. He has cleaned the ash lever and checked the holes under the pot to make sure they weren't plugged, we also checked all the small holes in the grates and they are clear. Can anyone think of anything that might cause the front of the pot to burn fine, but the rear of the pot to not burn the coal.

Again the front is burning perfect, the rear is only burning maybe 50% of the coal.

Thanks

Has this stoker recently been apart? My first thought is an air leak, either from a warped burner plate or a gasket inside the air chamber. You can see where the gaskets are in the pictures here: Pictorial: The Burner Pot Assembly w/part numbers

A worn burner auger/bushings can also do funny things, make sure the flights on the auger don't have sharp edges, and that the auger can't move up and down or side to side within the gooseneck.

Also, what feed and air settings is your friend using?

sorry for the delay, I had to call and ask him. He said that the pot was giving the same burn at the following set ups.

3 feed 3.5 air
3 feed 4 air
4 feed 4 air
4 feed 4.5air

the auger is in good shape and he is using the same coal that he used for the past year. The grates are in good shape and there has been no change in blower or motor at all.

So it burned good last year, but now with no other changes and the same coal...it isn't burning properly. That is odd.

Does your friend routinely pull the fines cleanout lever? If that was neglected last season there may be a buildup of fines in the air chamber. This won't be a fun job, but he will need to crawl in the base and look up through the clean-out holes to see if everything is correct.

Also make sure that after you pull the cleanout leveler, the cleanout door is closing tightly against the air chamber, and that the fines drop-out holes are fully closed. If everything checks out, I don't know what else it could be besides an air leak from an internal gasket. The next step is to pull the burn pot and troubleshoot it on the bench.

Is he burning rice or buckwheat size coal?

It wouldn't hurt to try bumping up the air relative to the feed - I recently had to do that using the same coal I used all summer. If more air doesn't help, I'm with Rob on checking the air chamber; strategic use of a mirror and flashlight might avoid some of the crawling in part, and working through the holes you should be able to clear any buildup. If that's not it, it would seem like the air is having too easy of a time getting into the front relative to the back, so x2 on checking the gasket at the bottom of the burn plates and the tightness of the fit between the plates.

Mike

Remember to pull the cleanout lever while the blower is running.

I went over to his house today and took a closer look, doors are fine grates are clean. I checked his settings to find that he was off on his feed setting. What he thought was 4 was a 6. So to make a long story short his feed was set way to high for his air. I backed his feed down to a 4 and his air a little stronger than 4.5. Hopefully this will solve the problem.

Next time I will start by suggesting a double-check on the feed and air settings. It is easy to skip over the simple things and assume they have been checked. Anyhow, good troubleshooting on your part. I'm sure it will take on a new attitude after your adjustments. Please report back with the results.

Also...if he is burning rice coal, you may be able to back the air down a little more. Next time you go over put a load on the boiler and after 30-40 minutes of stoking take a look at the ash ring.