McGiever wrote:could you write it up in similar format as like I added? What year model S130 is you friends? Wondering what years the Fuji was standard.
Freddy wrote:Good day. My buddy with the AHS130 is in his 4th year. This year he has had more puff backs than ever. The obvious reason is a change of coal. He is still using Kimmel Pea size, but it is a different truckload this year. Obviously it has different characteristics. The first 3 years he would have a subtle boom on rare occasion. This year he has been troubled with heftier puff backs on a regular basis. I'm writing now as he has finally made changes that have made a huge difference. Hopefully a total and forever difference.
Big change #1: He installed a draft inducer with a rheostat. He now has "dial a draft". He wired it so it only runs while the fan is running and maintains a draft of .04. That made a good change, but still he had some minor puff backs.
Big change #2: He finally figured out how to set the Fugi control. The factory found the manual & emailed it to me. Come to find out the control was locked. Attached is the Fugi user manual. On page 19 you'll find the Lock system. Even following the manual it's tricky to un lock it, but we finally got it and then changed the ash temps. Before the asher came on at 130 and shut off at 140. Now it comes on at 125 and shuts off at 130. If any of you have the Fugi control and have trouble let me know & I'll be glad to try & help. Basically he set it at a low of 120, a high of 150, a Hysteresis of 5 and then told it to shut off at 130. It's odd how the "150" remains in the equation, but that's how it likes it. The very last hing you do is tell it the temp you want it to shut off at. His asher is allowed to run whenever it wants. I understand some people have wired it so the asher only runs while the fan is running. If he ever has another boom, this will be changed.
Change #3. He added a thick paper-clip to the bottom of the flapper door.
At this point he has been boom free for four days. Hopefully his issues are a thing of the past & hopefully this info can help others.
pete6500 wrote:Been a while since I've read the posts. I left a post in regard to me keeping my fire as high up as I can so the fire is about 2" below the funnel outlet. I burn buckwheat and my flapper is the old style with no hole. I also have the grate timer which I adjust in relation to outside temp to keep the fire high. during high demand in cold weather I very seldom have to adjust it to keep the fire where I want it. One thing I have to mention, when the blower turns off and the flapper opens, I can hear and see the blue coal gas burning a nice flame. The key here is to see the blue flames. If I don't, the coal gas is not being burned and can travel into the flue by natural draft then get ignited. BOOM!!!! It's been fine this year with no booms as long as I maintain my fire high and nice blue flames. I hope this may help thanks for listening.
Bob wrote:Yanche wrote:What can we do with what we have?
1. Make the aquastat differential a minimum. This will get the combustion blower burning sooner, hopefully reducing how much the fire get disturbed because the blower cycles on and off more frequently.
2. Lower the ashing rate by lowering the grate motor speed. "rychw" is trying this.
I all this fails then what's left? Changing the concentration of coal gases so that an explosive mix doesn't exist, i.e. a purge of the boiler firebox. A control method is still to be developed.
I would add one element to the above list:
3. Raise the level of the burning coal in the firebox so that the coal gas is always exposed to an ignition source. To put it another way continuously burn off the volatile gases rather than letting them accumulate.
Bob wrote:In my own case, for the first time in the five years of operating the AHS 130 I have been completely free of puff backs for the entire season. The big change I made this year was reducing the thermo grate setting so that I also now see glowing coals even a significant time after the last fan operation. The other change for this season was a new load of coal (something I get every year) and until I have a couple more seasons with new loads of coal I have to note that a different coal supply might be affecting my results.
rychw wrote: I've noticed the there seems to be a correlation between the frequency of the puffs and the boiler running to reheat after domestic hot water call. That is interesting since the fire would not be as strong when reheating from hot water call as it would be from heat call.
*rychw*, How high is your fire?...What setting do you have for ashing?
Many pages ago I posted:
It would be interesting to gather members data on their ash thickness, fire thickness and unburnt coal thickness. The only way I could think of making these measurements would to to poke a coat hanger wire in from the inspection port down to the grate. Let it there a while and then pull it out. The cherry red would be the burning coal thickness, below it the ash thickness and above the raw coal. Any thoughts if this kind of data would be useful for comparison purposes?
Did anyone try it?
I haven't measured the fire but it is approximately 3 " below the funnel when the fan is running. My high temp is 160, my low temp for the fan to come on is 145. My ash grate dump temp is 110 with 5 degrees for my Hysteresis. I've slowed my ash grate motor speed by approximately 1/3 it's usual speed. I have continued to have puff backs that are mostly occuring when there is domestic hot water call.
McGiever wrote:I am sort of a rookie on some aspects here, but, hope someone more experienced might comment on your High and Low settings.
I'm thinking they would have a significant effect on those DHW calls for heat, but hesitate to advise.
Bob wrote:Have you tried operating with the high temperature limit set at 170 or 180 and using a 10 differential to see if it would help? From your description it seems as if the level of the fire is still a bit low to ensure that the gases are always exposed to a source of ignition and my theory is that the sensed temperature is affected by the boiler water temperature. Also--do you have the hole in the flapper door fully open?