Is Warm Morning Over-Firing?

I see two remedies.

#1 tighten up the air leaks.
#2 control your draft better

In my mind #1, would take priority over #2

Personally, I would do both.

Ok Ok, I'll look into an MPD and see if bringing the draft down does the trick.

Maybe next season I'll take her apart and seal it up as well. I may throw a gasket on the loading and ash doors just for giggles.

Still no takers on the double-baro idea?

There has been controversy over using two barometric dampers on one flue. I use a MPD and baro combination occasionally in the coldest parts of winter when my baro alone won't keep it under a .04. When you said yours is set to the max setting to achieve a .04 what does that mean exactly? You can't move the weight out any further on the baro door to lower the draft more?

What kind of baro is it? On mine, I put washers behind the weight to make it more sensitive. It's a Field Controls model RC.

Lightning,

The Baro is a Field Controls B-34T-J, it came with the tee. I've adjusted the mechanism to give the least draft possible, and have bottomed out the adjustment which brings the weight smack against the pivot plate. This did however get me to .04. But like Coalturkey and you have suggested, the MPD will give me that further adjustment if needed. I just don't like the idea of manual adjustment that leaves room for operator error. I like engineering myself out of the problem as much as possible

Do you remember what others have said against two baros? I'd ask the local shops here but they all seem to be completely incompetent and inconsistent with information.

So, with the added washers, you were able to increase the weight and thus gain a more sensitive adjustment. Hmmm, sounds like it might be worth a try...

But thinking through this, in my case (model B-34TJ), adding weight or lightening the weight won't get less draft since the volume of air is already at its max. So I either need to add more air volume escaping into the chimney, or restrict the flow with the MPD.

You must have a pipe damper for this stove. Put it within two feet of the exhaust collar. The hydrocarbon gas is where you get most of the heat in Bituminous Coal. So, it requires a different burning method than Anthracite.
If you pack the stove full of raw coal then you are going to rapidly produce large volumes of flammable gas. More than the stove can handle. Most of the heat value will be lost in unburned gasses and soot production. The gas that burns will cause a spike in temperature, much like stuffing a wood stove full of wood.
Another thing you have to remember is these stoves have a huge mass of brick in them. It takes a while for all of that brick to get hot. When it does, the stove will burn the gasses as designed, but; all of that mass will radiate a lot of heat. The stove is also designed to do that. The large mass of bricks will, by design; level out the up and down heat production of the Bituminous Coal.
Try this and see if it works. Hopefully, it will.
Load the stove with small charges of coal at a time. This will allow the hot bricks in the stove to burn off the gas at a rate it can handle and you should be able to maintain a cooler fire. It's a little more effort, but; that's the nature of the fuel you are using.
You just have to try different approaches and carefully observe what happens afterward. Soon you will be able to modify your operation methods to get the result you want. This stuff is part science and part art. That's the neat and compelling aspect of using a stove versus just turning a dial.

AKShadow wrote:But thinking through this, in my case (model B-34TJ), adding weight or lightening the weight won't get less draft since the volume of air is already at its max. So I either need to add more air volume escaping into the chimney, or restrict the flow with the MPD.

How about a 6" to 8" reducer and an 8" T and baro and 8" pipe to chimney...just my $.02.

AKShadow wrote:But thinking through this, in my case (model B-34TJ), adding weight or lightening the weight won't get less draft since the volume of air is already at its max. So I either need to add more air volume escaping into the chimney, or restrict the flow with the MPD.

Oh I see, the impression I get is that you can hold the baro door wide open and it won't drop below a .04. Well then, I'm not against trying 2 baros on 1 flue pipe. It makes perfect sense to me. It has come up before but was thrown under the bus saying it wouldn't help. I don't agree with that, but I haven't tried it either. Until proven otherwise, I think it would help in your situation. I say try it and post your results

michaelanthony wrote:

AKShadow wrote:But thinking through this, in my case (model B-34TJ), adding weight or lightening the weight won't get less draft since the volume of air is already at its max. So I either need to add more air volume escaping into the chimney, or restrict the flow with the MPD.

How about a 6" to 8" reducer and an 8" T and baro and 8" pipe to chimney...just my $.02.

I like this idea too. A bigger baro is gonna get you more air volume which should cut pull on the stove.

Lightning wrote:

michaelanthony wrote: How about a 6" to 8" reducer and an 8" T and baro and 8" pipe to chimney...just my $.02.

I like this idea too. A bigger baro is gonna get you more air volume which should cut pull on the stove.

And also massive amounts of soot production. You over cool the exhaust you get instant gobs of soot clogging goodness.

I'm looking at getting one of these stoves for power outages and such, and I'm reading this and making plans to put a Manual Damper on my stove.

Im planning on putting an MPD on this weekend and will post results!