Yellow Flame to Tri-Burner Conversion. What Do You Think?

StokerDon wrote: I even made a second combustion blower choke piece so I could realy lower the combustion air, still lots of black in the ashes and 80 to 110 pounds of coal a day.

I am totally new at stokers but shouldnt you increase air if your getting unburnt coal off the end? or slow the feed rate? As I said Im new at stokers and have a lot to learn so Im probably wrong but I cant figure out why

waldo

Waldo,

This is not the case where unburnt coal is falling off the grate or lit coal falling off the end of the grate, that would be to high of a feed rate as you correctly pointed out. This is more about how thoroughly burnt the coal that ends up in the ash pan is.

That being said, you may be right as McGiever pointed out the small chimney may be causing me to run to little combustion air and resulting in the unburnt coal.

-Don

Insulating the boiler and piping will make a measureable difference. Do that first.

Consider a secondary blower to maintain the idle fire. Keystoker added it to reduce unburned coal and outfires.

Yah, I should insulate the boiler and plumbing. The main problem there is making it look cool with all that covering!

The small constent blower idea that Keystoker uses is a very good one. I'm not sure how they do it though, do they have a seperate inner channel for it to blow through, seperate from the main blower? If they don't, then the continous air would blow out the bottom air inlet as well as the fire box. I have not been able to figure out how to do that on the Yellow Flame yet.

-Don

Post here:
Upgrading Older Keystoker Boiler With a Secondary Blower

Cut a hole exactly like the photo shows. The air will be forced to the bottom of the grate. You won't loose any because of the natural draft pulling air through the fan wheel anyway. It'll work great.

Rev. Larry
New Beginning Church
Ashland Pa.

McGiever wrote:Post here:
Upgrading Older Keystoker Boiler With a Secondary Blower

Thanks McGiever, That answers that question. I will need to figure out something a little differnet for the Yellow Flame though. The Keystoker type blower attachment goes right where the linkage mounts to the blower housing.
Don't worry, I'll figure something out when the time comes.

One possiblity would be to use the other 3 grate stoker I have. The linkage is totaly different and does not mount to the blower housing at all.
I took the Tri-Burner template to a fabricator on Friday, it will be done next week. After I do some re-plumbing and plumb in the Boiler-Mate it will be time to fire it up for DHW.

-Don

Don, before you make too many big changes to the Yellow Flame I suggest that you try coal from a few different sources. I have had some that burns very completely in summertime use, and some that puts a lot of unburned pieces in the ash. A few days ago I started burning some new rice coal and noticed a lot more unburned coal in the ash. The coal is very hard, and the timer cycles just aren't enough to make it burn all the way. I cut the feed rate back and increased the air a bit, but that is all I can do.

Sorry Rob but, down here there aren't many options. There is a place that sells Kimmels about 3 miles from my house $245 per ton, $20 per ton for delivery (completly crazy). Then there's a place about 20 miles away that sells Blaschak for $205 per ton delivered to my coal bin.

Last winter I did get a half ton of Kimmels when the other supplier ran out, I didn't see any difference.

-Don

SD, You going to run a combustion fan independent of the carpet motor?

For those who may not be familar w/ TriBurners, they use a single motor w/ dual shafts...one side drives reducing gears for slow stoking and other side spins full speed squirrel-cage fan.
So, no stoke = no fan/air.

Some TriBurner owners have found it benefical to disable the stock fan (remove squirrel-cage from shaft) and add/mount on a new separately controlled blower fan to run independent of stoker motor.

My plan is to run the Tri-Burner as is at first. If it doesn't put out enough heat, I will add another blower.

Also, I will use the Alaska reohstat to set an idle air/feed rate. Then when thiers a call for heat or a timer cycle, the stoker/blower motor will go to full power. This should yeild a nice complete burn. If it all works.

-Don

I seem to be in the minority on this topic, but I am not a "fan" of secondary combustion air blowers as advocated in some of the previous posts. IMO secondary blowers are generally unnecessary and counterproductive for several reasons. Running a combustion blower when there is not a call for heat takes the BTU's from the coal on the grate and pushes them up the chimney as waste heat. With little or no burnable coal on the grate, the fan is blowing cooling air through the dead ash into the combustion chamber, ultimately increasing the amount of coal that has to be burned to maintain boiler temperature. When there is a call for heat, the burn grate is basically empty, so there is a delay while the unit runs to fill it up again. Not to mention that the blower running 24/7 uses electricity, draws make-up air into the house and creates maintenance requirements, and that having the fire high on the grate moves it closer to the hopper and contributes to some small risk of a hopper fire.

From this and other threads on the forum, my understanding is that the main reason people want secondary combustion air fans is because they reduce the amount of black coal in the ash. I agree they do that, but for the reasons outlined above I believe it's false economy. Personally, I'd rather burn less coal and have the unit be more responsive when needed, even if it means there is a little more black in the ash.

Am I missing something here? I freely admit that I like the older equipment, but I also try to keep an open mind about ways to make things work better. So far, I don't see how secondary blowers are one of those.

Mike

To my knowledge, Keystoker introduced the secondary blower to reduce outfires. If your chimney doesn't maintain adequate draft between timer cycles, outfires will be a constant nuisance. Ask a guy that went from 3-4 outfires per week to none after installing that small blower.

I saw StokerDon mentioned an occasional outfire, but it seemed like most of his focus, and that of other posters, has been on the unburned coal issue.

Even with an underfeed stoker, I used to have outfires when I tried to skimp on the summer settings. I found keeping the winter feed rate and bumping up the air seemed to solve the problem. But you can bump up the air without using a secondary blower.

If that didn't do the trick on a Keystoker, my next suggestion would be to consider adjusting the thickness of the coal bed. I still think the secondary blowers introduce tangible problems, and wouldn't mess with them over unburned coal. Even with outfires, to me they should be more of a "last resort" than a "go to" option.

Mike

I don't run an inclined bed stoker, but I expect that by increasing the feed rate and air to eliminate outfires and some point you cross a line and burn more coal than someone running a lower feed rate/air with a small amount of air from a secondary blower. Average boiler temperature also plays a roll.