Yanche wrote:The various comments about fire height are interesting. Perhaps sensing bottom ash temperature is not the optimum ashing sensor control location. Could absolute fire height be a better indicator? Isn't that what we instinctively look at when decide to shake a hand fired boiler? Coaledsweat, what did you look at when you were running a hand fired boiler? Do you think it's possible to do it with a sensor?
Still thinking about this one. I don't think the location of the probe is the problem, I think it's the speed the ashing runs at, It pulls the fire down just to satisfy the off setting and that makes the coal grumpy. It just ashes too fast.
Can these AHSs be set to ash within one, two or three degrees? If I was experiencing this problem, I would stop ashing until the fire breaks the surface, about half way up the supply of coal pyramid. Start the asher and reduce the differential a bit, I would guess about 80% of what you had and maybe 60% for something that is seriously booming. Watch the fire for the next few days and make sure that it periodically returns to the surface. That means glowing coals under load and ashed coal when idling. It won't be on the surface all the time, but it needs to pop up every now and then. If the fire starts to disappear in the fresh coal, you'll need to slow it down some more.