What's too hot for a harman mark III?

I started to use a harman mark III in our basement to take some of the load off the stoker on the first floor.I filled it to the top of the top of the front fire brick and slopped it up towards the back of the stove.I have the air draft open about 1/4 of an inch.i use a barometric dampner which currently is fully open.Strong draft chimney.I'm burning a mixture of nut,pea and stove coal. When the intire coal bed is burning the stove top is reading 800+ deg of heat.Nothing on the stove is glowing. Is this type of temp normal or i'm i going to wake up one morning to find a big puddle of steele???

Hello, I have the Harman elite insert, same size fire box. I set the draft to 3/4 to 0ne turn or revolution and the temp stays about 300 for me. I also fill my fire box full with nut coal as you describe. Hope this helps until someone with more experience chimes in.

Have you measured the draft with a manometer? The baro's capacity may be exceeded if it stays full open all the time.

Are you running a blower on the Mark III? If not, the temps will be higher.

What's the pipe temp before the baro?

On my Mark I can run 1 turn open, pipe temp. before baro abt. 200, running the draft at -.05 WC., with a full load as you describe, blower on.

It looks like 1/4" is over 4 turns open. That sounds like WAY too much to me.

Right now with straight pea I'm at 2 turns and my vent temp is 300 before the damper. Now that it's going again from overnight I'm cutting back to 1.5 turns.

When I was trying nut coal the other day I was suprised that I could get the same temp with only about 3/4 of a turn open.

Steve (newbie)

I missed the 1/4" open on the draft. That is way too much. I run 1 to 2 turns from closed, maybe 3 for a little while if it's cold in the house.

The draft was set .04 with a gauge. The baro only goes full open when running that hot.I turned the draft out 2.5 turns and it maintains 450 to 550.Which is nice so far. With temps in the mid 20's at night the stoker is only on idle mode.It's still using the coal i put in the hopper over a week ago. I'm shocked at how the mark III burns the coal. it's mostly all ash. And it can throw some serious heat. The kitchen stays alot warmer. Which was my biggest problem last year. The kitchen always stayed 20 to 30 degrees cooler then the rest of the house.That was due to the way the house is built and it never got good air flow into there. now with the mark III in the basement and basement door open u can feel the heat coming up the stairs

Sounds better. Do you have the blower that mounts on the back of the stove? It greatly increases the heat output.

Yes it has the blower on it. Helps move the air in the basement around

I started up my Mark III friday nite, and it's been smooth sailing so far.
We had a low of 14 here sunday morning, WOW.!

anyway, I like to see my stack temps running around 200...
a little less on warmer days, and a little higher in colder weather
where daytime highs stay under 20.

I usually am turned out 1.5 - 2 full turns on the draft
control. I am finding that a good shaking twice a day is
all i need... but i mean a "good shaking". I think the first
couple years I didn't shake quite enough, and could get a low
fire after 10-12 hrs,,, but now after burning a full box, i can come
shake and load much quicker if i get her shook down real good.
I shake until i get some live embers coming thru the grates, and
i see a nice full orange glow in the ashpan from the grates above.
this keeps a more constant flow of air, unlike when i didn't shake enough
and was getting too much ash built up.

rarely do i ever see temps over 400, only during startup or if trying
to rebuild a severly low fire.

As I mentioned, my Mk I runs about 150 tp 200 on the stack at 1 turn, 3 turns can go up to 300.