From a deceased and badly missed member here...
whistlenut wrote:Alex, I have an EFM DF520 and had a 900 for 3 years. I have worked on and installed a few AP520's, a 700 another 900 and take care of a bunch of other boilers. Your question about the fines build-up in the transfer head is related to Axeman units is answered by saying there is no access door specifically for that issue, however you can take off the 3 nuts on the transfer head and pop the cover to see what is causing the issue. Usually the sacrificial Brass Split Rings are worn beyond tolerance, and allows the fines to migrate out to the floor, or stay aboard and cause rapid wear. The entire head is removable if you need to go that far, and is a once in 15 years adventure. In an AHS, EFM, Keystoker, Yellow Flame and a Van Wert, it is a non issue.
I suppose you are aware of the 'fines lever' on a EFM350 or 520, but the larger models self clean. This may have been your original question, but the 'fines' are not an issue unless wet coal is added to a barrel or bin feeding an EFM. EFM has a removable plate to access the bottom of the burn pot, and I suppose that you could remove and clean from that angle. It is pretty accurate to say that these rigs are VERY dependable and with modest care will last a couple lifetimes. If you choose an inclined flat bed stoker, you have even less parts or complexity to deal with. I have burned in most available stoker boilers and will say again, that all of them are very good, some are even better, depending upon what your needs are.
And here is another discussion...http://nepacrossroads.com/about28254.html