Using a Stove Pipe Damper

It's been unseasonably warm this week, expirament should be back on tomorrow morning.

 

Grizzly Adam and Old Spark

With these Drolet Myriad stove's fireboxes having great control of the input air and being able to close it all the way down (Unlike my old stove).

And with these stoves not holding the heat in them but radiating the heat out so well...............

I find loading them up with a little bigger hotter coal bed gets the new wood off gasing faster and I can get the stove shut down sooner to a low burn and nice secondaries.

I can do this as no fear of a run away stove having the extra ability to control the primary air to extra low levels.

Old Spark can you snuff out your fire by closing the primary air all the way as your flue as I remember has some good draw?

Plus having the bigger stove I have the room to have a bigger coal bed and still have room for a nice load of new splits.

 

I can snuff mine out if I close it completely, so I leave it ever so slightly open. Loving the huge firebox and significantly less ash for a more complete burn!

 

That would be cool ,I would like to see the results

 

Can we resurrect this thread Grizzly Adam? I'm curious of your results 4 years later. Do you still have the same stove? Is the damper still installed? I have one in my double wall pipe for emergencies but haven't really tinkered much. Just wondering what you've found over the years...

 

Marvin , I have one installed on top of my Buck 81.. been there for 5 out of 6 seasons of burning.

I found that I have better control over the fire with varying outdoor conditions.. a calm 40 degree day gives a lot less draft than a -10 night with howling winds...

Having better control has allowed me to burn less wood.

Having the stove pipe damper has allowed me to delay replacing a less than perfect gasket on the door which would otherwise allow too much additional air to leak into the stove..

With the stove pipe damper, I am able to leave the primary air control open more. I am convinced that this leads to fewer coals left in the stove at the end of a burn.. when using just the primary air to control the burn, I was shooting for only having flames up by the secondary burn tubes and not near the wood... it seems that doing that limits the amount of oxygen available for glowing combustion and thus leads to more coals... if I didn’t explain that well, let me know and I’ll try to rephrase it...

 

This is one of the reasons I was curious. It's looking like I can limp this gasket through the rest of this year but will definitely be replacing it for next year.

I get what you're saying about more primary air to better burn down coals.

Do you mind elaborating on your operating process? Do you set the damper first and then start adjusting the primary air control or vice versa? Maybe some sort of combination?

I think I will start tinkering with mine. When my nc30 is cruising at 650-700* STT my flue temp is often running at 850-900* (double wall with probe). I keep thinking this seems pretty high but just started thinking maybe my probe loses accuracy as it goes up because it stays pretty consistent with the STT while the fire is building. At least I shouldn't have to worry about creosote buildup at those temps

 

Sure, happy to oblige... so when I’m doing a reload, I first open the stove damper straight up and down. Then primary air completely open. The combination of the two gets a draft going which pulls ash away from the door to reduce the amount that spills out.., I then shut off the blower if it’s running. Then I open the door,,, Rake coals forward and reload... I close the door and wait for relight.,, Once the firewood lights, I put the damper at about 45 degrees and close the primary air by about 20%. This generally allows me to have a controlled fire while slowly growing and heating up the stove... as the temp increases and I start to see secondary combustion by the burn tubes, I’ll close the damper to about a 20 degree angle and closer the primary air another 20%.. after that, depending on what I’m looking for (lots of heat or overnight burn) I’ll make minor adjustments for desired results... on the coldest of days, I can have the damper almost completely closed and on warmer days! I leave it open a bit more... 30 minutes into a burn, I generally have it adjusted where I want it... I rarely completely load the stove but instead tend to load about 1/2 to 3/4 of the way... I rarely load in fashion that would allow me to make an entry in the Stove Tetris thread.,,

 

Thanks stuckinthemuck! Great info! I'm gonna do some playing over the next few days as it's supposed to get cold again.

 

When complete, report back with your results!!

 

Will do!

Where do you have your damper? Mine is about a foot above the stove outlet and about 3-4 inches below my probe.

 

This is pretty much what I do also, build the heat in the stove as fast as you can to get the secondaries to light off, then close the damper and adjust the air control. I agree with getting less coals build up by closing the damper more and leaving the air open more. In our last house which was a 35 foot masonry chimney, the flue gas temp was almost always higher than the STT, in the new house which is 22 feet of class A, I can usually keep the flue temp well below the STT during active burn.

 

I am still running the Drolet. I swapped the stove pipe this year but didn't plan ahead very well. It was cold and I was in a hurry so the damper didn't get installed at that time and I greatly miss it. I will be reinstalling it when the chimney gets cleaned in the spring.

 

Reading this old thread and found the quote from woodheat.org (site has suspect info anyway) that controlling the intake air is better or more effective than adding a damper. That's bogus when talking about modern noncat equipment. First off, you can't really control the intake air. The primary air can't be closed all the way and the secondary air is always wide open except on the PE stoves. Then, if you read the manual, your stove was designed and tested with a maximum allowable draft spec. Shutting the intake doesn't change the draft strength, you need a flue damper to do this if your draft is too strong due to height or weather conditions. Noncat stoves pretty much always pass the same amount of air through the firebox, reducing the primary air just causes the secondary system to flow more air. Need to meet those EPA emissions specs!

 

I love pipe damper talk!

 

I have seen this a few times in these parts, but am pretty sure it is not accurate. The primary is a great big opening, the secondary is quite a bit smaller. So restricting the primary will reduce total airflow, quite significantly.

 

I think you have it backwards, the secondary hole is huge on the NC30. Then the doghouse holes also are each penny sized and wide open! The 6" flue keeps sucking, closing one hole down just makes the others flow faster.

The primary is not that big. Take a look at your NC30 primary intake, you can see it from behind, the three inch OAK stub is large but the actual opening is inside and is very small. During startup you might have it full open but as you close the primary it is not linear, it closes fast!

We don't know how significant the reduction might be but I tend to agree that there will be at least some small reduction in total flow.

 

Great post and explained well.

 

I should clarify, even though a ton of air is always flowing through a noncat, the secondary air is up above the fire so not necessarily feeding the main fire but acting to clean up the smoke. I do think most noncats are controllable, my nc30 can be snuffed easily! They seem to work best when running hot.

 

For me, Having a flue damper in the stovepipe is what tunes my burns to perfection. Really, the damper plate acts like the choke valve on an engine. When hot, keeping the combustion gasses pressed into the stove. The primary air adjusted to meet fuel load & keep the secondary combustion active. Its really become an easy task lately, keeping the first floor of the house warm on wood heat. But in the end, burn control is pedestrian once you have properly dried firewood now and 3 yrs down the road...