I used a 3” flex auger for ash removal for 2 ahs260 boilers.
First tried with a 348rpm gear but it created some sort of harmonic vibration (over sized slinky going all wobbly in a pipe
). Switched to a 129rpm and all is well (have a 250rpm auger on another boiler working well also).Auger runs on the ground between both boilers then 45dg up and out of building for a total length of about 18’.
I cut two 3x9 inch holes with 3 inch of pipe between per boiler for the ash to go into, auger busts up the clinkers and sends everything outside to a pile (will use a 55 gallon drum next season) Used sanitary tee for the drop outside.
It runs for 28 seconds at the start of an ashing cycle removing ash from previous cycle, either boiler can start auger via relays.
I have about $800 in auger components and another $100 in relay controls. Works pretty well but bridges maybe once a week when under heavy load (400 to 500 lbs coal per day per boiler), just need to poke with a stick.
All in all it saves me another daily chore
Kevin