Stack Pipe Temps

If other forum members have temp gauges for your smoke pipes, what temp readings do you get on average? And how far from boiler flue is your temp gauge located? Also, if you have a manometer, what readings do you have?

My AA260 has a temp gauge on the smoke pipe about 3 to 4 feet from boiler flue. I now get temps just below 400 degrees F. Obviously, my temps coincide with my fire pot, if it is at full capacity, burning hard etc. I had been getting temps at 425F in the past. I turned my anthrastat down this season a bit. I think I may kick it back up so the fire pot fills a bit more and gets my stack temp up a bit. I noticed when I have the 425F my steam radiators fill much faster. I like that! But, I guess its all a trade off. My manometer is pretty consistent between .04 and .06

Anyhow, I'd like to hear your readings.

Hi Townsend, You are getting 400 degrees on the pipe 3-4 feet from the boiler? That seems high to me but, I'm using a hand fed furnace. Currently I have around 165 degrees at 12 inches from the furnace, on the top side of the pipe. I'm sure that more people with stokers will chime in.. Is there a barometric damper between the temp gauge and the boiler?

I'm concerned that you might be loosing too much heat out the chimney at those temps..

Hello Lighting. There is a baro but not between the two. It's after the thermometer right at the wall where pipe goes into chimney.

Of course that temp is at full blast mind you. At idle it's much lower.

125 about 4 inches from Keystoker 90 chimney connection, at the top of the stove, running medium feed. No manometer readings that takes a little for me to setup. I am in the process of connecting combustion air to outside air through a chase on my block wall. Tuesday I will have all my hardware to make those connections. I am having some issues with the cold air supply, the 2 inch PVC pipe is condensating

Oh ok, that makes better sense. Mine is running at only about 25% capacity right now..

Guys, I think he was asking about internal stack temperature, not the surface temperature of the flue pipe.

With my stoker set at 12.5 lbs per hour, the stack temp (probe thermometer 12" from flue outlet) tops out around 400F. Cheapo magnetic thermometer on the flue pipe is usually about 180F when running hard. Idling you can hold your hands on the pipe.

Yesterday I worked on a Keystoker KC10, after 20 minutes of stoking my probe thermeter read 380F. I expect it would get to 400 or so if it ran longer, the fire was still not full size.

Yea, it really gets quite a burn going. Especially trying to build steam for my large house.

How's your Clayton running Lightning? What size coal you using? Looks like a nice setup.

Thanks Rob, I should have clarified. I have an internal temp gauge. My outer pipe temp is much lower. Rob, is 12.5 a heavy load or just average?

Sierra, that outside air should help a lot. Where is the condensate forming?

I would rename the post stack internal temperature to keep those like myself from responding.

Awww, I like your response! Makes me feel wanted! Moot point now anyway if the read this far.

12.5 lbs/hr is at 100% duty cycle. It is pretty unusual for it to actually run that much in my house. A few times per year it might run steady for a few hours (subzero with strong winds). Right now I am burning 50-60 lbs per day, so the runtime isn't much...stack temp rarely crests 325 right now.

In theory I could double the output of the stoker, but I have no clue what the stack temperature would be.

2001Sierra wrote:I would rename the post stack internal temperature to keep those like myself from responding.

You are welcome to share your figures, just be clear what the measurment is so it isn't comparded to the wrong thing.

Townsend wrote:Yea, it really gets quite a burn going. Especially trying to build steam for my large house.

How's your Clayton running Lightning? What size coal you using? Looks like a nice setup.

I'm sorry I was confused about your internal temps..

The Clayton is doing great! I've been doing my incessant tinkering with it as usual.

I'm trying a nut/stove size mix this year that I'm really liking!

Ok, I had a call for heat a little while ago and went downstairs to see temp. I'm very pleased. Right at 400. I had been closer to 380 so I think that small increment of 20 degrees helps. My rads are filling up nicely and the cycle is a moderate amount of time.

And I added a pic of the boiler pressure. Mere ounces!!! Don't let anyone tell you that you need pounds for steam to work properly! That's a 3 pound gauge by the way.