1500 F stack temp

[Bricklayer]

I've got a home made arch with a 2x5 continuous flow flat pan. I can get it boiling right to the float box with cold sap coming in not preheated running 1" depth at 1200 F . But i get my most draws at 1500-1600 about a litre every half hour or so. Pretty scary temps but she boils like mad. I have about 1 inch from the bottom of the pan to the ramp. And I have a blower. Is it normal to run these temps? I am going to maybe look into AOF but not in the next couple years. I get flames right to the stack but only sparks at night no blow torch out top of stack. I'm burning a mix of hardwood pallets and split soft/hardwood mix. Firing every 7 or 8 minutes.

[one more]

I read your post and grabbed the thermometer of the wood stove and I'm getting around six hundred degrees on the steel arch of the oil tank. The pipe about two feet from fire was 350. I say if the rig can handle it let it run?

[sugarman3]

At that temp,you are blowing heat out the stack,you should try to get between 900-1000,you will boil just as fast ,pallets burn hot,turn the rheostat down if you have one on the blower,you should see just a good boil.

[Ghs57]

I'm reading about 400 just above the base stack. This is with AUF/AOF added this year. It makes a huge difference that you can both see and smell. No smoke out the stack. It seems like the heat is staying under the pan. Firing every 6.5 minutes.

[Sugarmaker]

We use stack temps as a indicator of how the rig is running and or how we are firing it. We run about 500 degrees F with a bolt on stack thermometer about 5 feet above the arch. Every rig will be different. Boiling like mad is pretty much what you want to do!:) Remember that your only about 15 seconds from disaster when running one of these!:) Keep safety in mind at all times. Have some back up plans, should things go south.
Regards,
Chris

[1arch]

my stack probe that reads out electronically on my auto draw indicates 700 to 900 when I'm cooking good. Temps much over 1000 and sap is jumping places I don't want it t go. My old mechanical probe is still in the stack and in comparison it is showing 1000 to 1200 degrees. So for years I thought I was running about 1100 degrees however trust the digital probe is a far more accurate technology.

[Bricklayer]

I tried turning down the blower but I was still getting the best boil and draws at 1500 f. Noticed the back of the stack was glowing red and the angle between the stack and the pan was red also. I might try raising the ramp up to 3/4" away from the pan and turning blower right down. I have noticed that when I have blower on that I have leaks in the sides of the arch where air is escaping. Not going to be able to fix that till season is over. I think some high heat silicone at the joints under the brick and blanket will fix that. My thermometer is a probe type dial thermometer by SBI. So it's reading the internal stack temp not the surface temp of the steel

[binski]

I switched from the same dial temp probe to a thermocouple and digital readout. The reading on the dial is about 300 deg higher than the thermocouple. I use my stack temp reading like Sugarmaker stated, how the rig is running. It tells me when coals/ash started to build up and when I am wasting heat up the stack. I run mine between 500-550 with the probe 3' above the arch. When I built my auto draw off I built the readout for the stack. I'm surprised how much I look at it during the day.

[Bricklayer]

That's how I've been running mine also. I plan on building an auto draw off this year and will also be putting a pid in for stack temp. Once my stack temps start to drop my stack starts ticking so I know it's time for more wood. I also just blow my air into the back of the ash box. If I made a manifold to blow it straight up would that make a difference. If I don't turn the fan off while loading I would loose every piece of meat on my head is that any indicator or is that normal while blowing air into the back of arch?

[binski]

I shut my fan off every time I fire (8 minutes). Keeps the ash from coming out and flames from burning off my eye brows. I wired a switch for the fan right by my the arch door.