barometric draft control

My daughter is buying a used Kast 11 Alaskan. She has to install a power vent as there is no chimney. The dealer told her she needed a barometric draft control also. Is this so? I really enjoy the posts. very caring and knowledgeable folks here. thanks.

I have a Channing III from Alaska with a power-vent. As I understand it, the Barometric Draft Control is meant to keep some of your preciously generated hot-air from going out the chimney (or power-vent as the case may be).

The power-vent (or the standard draft from the heat-difference in the stove vs. outside) may be sucking more air than you'd need to send out just to get rid of the exhaust of the fire. That other gas it would take with it (if you didn't have a draft control) would be hot air from in the stove. The B.D.C. attempts to let the extra air that the power-vent/draft is sucking out be the (less desired) cooler air instead. The B.D.C. tries to be an automatic mechanism for doing it, instead of a manual damper.

Someone with more experience correct me if I'm wrong.

http://www.ddchem.com/draftcontrols.htm has a picture and description about 1/2 way down the page.

The Barometric is a must with coal.
Most of the old codgers around here (which I am one) think you should have a chimney to burn coal as God intended. I guess if the dealer installs the power vent properly it should be fine. I myself would not because of the power outage issue, however there are ways to deal with it.

thanks for the replies. A big help. As for power outage, the combustion fan won't run w/o electricity anyway.
It's getting installed on Friday by the serviceman. Should be okay.
again, thanks.

the link you added is one of the manufactures of baros. i have something simpler(cant remenber the name) and its not of the quality (less durable) that is shown.

great illistration/explanation of how it works.

I use the RC, real good unit. If a pro is doing it you'll be fine, and warm!

Question concerning a baro damper? ( This entire thread should be under the 2nd category , controls )

From what I am reading, it is much more critical to have a baro damper installed on a stoker or any other unit with an induced fan moter. Is this true? And not so critical on a quality hand fired unit with the manual damper on the ash door? Is this correct?

I have a baro damper installed and I admit I never used the meter to test my draft but it seems to stay closed at all times even at the lightest setting.

So last week, I wrapped foil over it and my stove tends to work much better and I have better control over the heat output. I've been running 150 F stack temps and 130-150F air temps blowing into the heat accumaltor. This is my lowest output with 3/4" turn open on ash door damper. If it is colder out ( below 30F ), I can open the damper 1.5 turns and run 225F stack and 200F hot air. And I can continue to crank up the heat output as necessary. I am sure I can fire this unit to 300F heat output if I wanted too. And she runs hotter & more efficent longer into each fill cycle. My stack & heat output temps move closer together.

Why do I need the baro damper on a hand fired Harman?

To prevent overdraft.

How do I know if I am pulling too much draft?

My unit maintains a constant temperature for many hours through the cycle from one shakedown & reloading to the next.

I'm no expert but I think it goes like this, 99% of the time you absolutely don't need it. The time you need it is when conditions change (variety of reasons) you do not overfire your appliance and have a consequence or worse is my understanding.

Oh, sorry about that, yes it is more important with a forced draft unit. My boiler has a combustion blower and I would not run it without a chimney and a Barometric Damper.

Cap, if you had a night of very cold weather, with a strong wind, your chimney would pull a lot stronger than normal.

You might experience a faster, hotter burn of your coal. If you monitor your burn temperature, and pay attention to the draft control, I would say you don't have to purchase a baro damper.

Greg L

yeah like last night

My Harman held tight control last night with temps in the teens and average wind speeds of 18 mph. At 10p, I had the damper open 3/4 turn, 130F hot air out and 150-160F on the stack and alum foil wrapped over the barometric damper. My observations after some late night testing: With the baro exposed to basement air ( removed foil ) , my stack temps will drop 20-30F but I will also experience a drop in hot air outlet temps. I believe it is somewhat relative. It seems as if I can maintain control without the baro, unless I am missing something. I'll continue tinkering.

Well, I am interested in what you can discover in this experiment, just make sure you are careful. A runaway coal fire can do some serious damage.