Chimney Draft Failure

coalcracker wrote:See what happens when you close the flue pipe damper ? Your draft goes away.

No. Way...

coalcracker wrote:Open the flue pipe damper, better yet remove it and scrap it, and open the ash pan door, you won't have a low draft condition. I haven't had a low draft condition in 20 years. Better yet, buy a Harman.

Open the ash door so my furnace melts into a puddle of glowing iron? You can't be serious.

coalcracker wrote:wait , I just realized, you're running a baro damper AND an MPD, on a coal stove. You'll never get that to burn right...this is hilarious.

Hilarious... have you tried it? I get 18-24 hour burns that only vary by a few degrees without being touched..

coalcracker wrote:Better yet, buy a Harman.

What the hell is a Harmon?

coalcracker wrote:Realize if you put enough obstructions in the flue pipe with those gadgets, you'll never have consistent draft.

Ok. I'm done bein a wise guy. Best of luck to ya Coalcracker!

It's poor advice and lack of knowledge that creates dangerous situations. Understanding draft isn't exactly rocket science. Understanding how draft and dampers work are a fundamental part of burning coal. Like Rob R mentioned, every stove and setup is different. The best advice is to follow the manufacturers specs. I could see the bashing now... .

My stoves manufacturer recommends a baro, but I haven't got the room behind my stove, so for now I'm using an MPD and trying it out. but I understand to set the baro correctly, it's beneficial to have an MPD B4 it to adjust it correctly. I'm able to monitor my draft with a manometer, and so far so good.
However, recently I'm having a tough time keeping my fire consistent. I'm adjusting the draft with the MPD, and the thermostat, (air intake), but the fire won't take off. The other day, when I initially fired up the stove, it took right off, but with-in a few hrs, all temps on the stove were falling. Then I realized the outside temp (@ midnite) had raised from 42* to 52 and "wet" outside. Because of the warm temp, I just let it fizzle out. Today, I'm attempting it again. Got it to take off relatively quickly, but now, once again after a couple hrs, I'm fighting to keep it going.
At 1st I set my MPD, (almost closed) to reduce the draft from .08-09,down to about .04-05 (manufacturers recommendations), and closed down my intake to normal. About 15 mins later the fire was dull and temps were less than 300*. So I opened "just" the air intake (thermostat), but to no avail. To sum it up, (cause I have to leave), opening the MPD and bringing the draft up to .07, "visually" the color is coming back. However the thermometer on the heat exchanger, is still less than 300* Maybe things will settle down when the stove has been on a few hrs.
Lightning, I hear you talking about primary air, and secondary. My stove only has one intake port at the rear of the stove. Does yours have 2?

Hi Joe, I recently installed a secondary air distribution system. Here is the thread for it. There is a video link on page 6 I believe

Secondary Air Distribution System

Thanx Lee, I'll check it out.

joeq wrote:My stove only has one intake port at the rear of the stove. Does yours have 2?

You stove has a series of secondary air ports as holes by the glass door. It could be they are letting in too much air over the fire and starving the primary air. Try blocking some of those holes off.

Your stove has a thin coal bed so secondary air is not as critical as with a deep bed. The Franco Belge uses no secondary air and works fine.

sounds like this is common today...No Wind... Smoked Out the Basement

Well said Lee ,well with all the things I have been through dealing with a draft loss I'm 100% sure that 99% of the time its the chimney and not the equipment that your running but I don't have 20 years behind me and I have a Hitzer insert with a Baro .Keepaeyeonit

franco b wrote: You stove has a series of secondary air ports as holes by the glass door. It could be they are letting in too much air over the fire and starving the primary air. Try blocking some of those holes off.

I'm very meticulous when scraping the grates and ensuring those port covers are closed, but thanx for the info Franc. Now that the stoves been running almost 7 hrs, it seems to be settling in. We'll see what morning brings after a long nite (for this stove) of no attention.The outside temp is now in the 20s, and I opened my MPD a tad to raise my draft a little high to .06. I also slightly closed off my primary air a touch, so hopefully the coals will be ablaze when I wake up.

It's best to look at any chimney draft problems from a practical standpoint, if there are multiple devices installed along the flow path that are specifically designed to impede and limit the exhaust flow, it's only logical that particular stove/chimney setup will display a lower draft, or possibly not enough draft, to successfully burn the stove with good results. The stove will become very sensitive to any drop in barometric pressure, because these devices are limiting much of the draft to begin with. Even if a fpd or baro device is completely open, the flap being vertical still presents a minor flow restriction to the stove, instead of a completely open pipe. In an internal combustion engine, people pay big money to port the cylinder heads and intake manifold passageways, just to get the engine to breath better and make more horsepower, and therein lies much of the added power over a stock engine. Gas flow is gas flow, controlled by the laws of physics. Likewise, installing multiple flap valves that close completely or partially in a chimney, is going to have detrimental effects on the stove draft- because by design, that's what these devices were intended to do. The stove may work ok or barely in a high draft condition, but if the draft falls off due to less barometric pressure, a stove set up like that, will tend to go out, or heat very poorly. I've seen a lot of stoves with no damper, with manual fpd's, and a few with baro dampers- the worst problem I've seen, is a coal stove with a baro that would not even burn, and constantly went out. The next worst setup I've seen, was a coal stove with the exit pipe angling down, to make it under the mantle of a fireplace chimney- that stove won't burn coal well at all, and only works with wood. Coal requires a strong draft to burn. Anything done to lessen the draft beyond the ignition point, results in a stove that won't burn or heat, and goes out. I'd rather have a stove letting some heat up the chimney, than one that keeps going out and won't even start. So there you have it.

cc, you appear to be an expert on finding the extreme rarity & taking it for gospel concerning ALL heating devices--I feel bad being the one to share this with you--but, you are WAY off base with your knowledge or lack of same. If you've got some hands on knowledge, I know I'm all ears, but just reading something in some biased mag or book does NOT impress me in the least. Explain your set up! Not encyclopedia Britannica's.

The worst draft problem I had , (recently), was when my 90* cleanout tee was clogged solid from a few winters worth of ash build-up. "That" kinda caused a flow restriction. And altho I can appreciate your comparison to the internal combustion engine, I don't think it's on the same level as a coal stove. A 6" pipe supplies far more area needed for complete combustion on a coal/wood stove, for the necessary speed of the exhaust going up the chimney, than a 1 7/8ths hedder tube on a cylinder of a 455 at 6000RPM. A baro doesn't provide "any" restriction in the pipe, while an open MPD valve is miniscule in area for the exiting gases. My stove Co. engineers recommend an .04 draft to operate efficiently, and only an MPD or baro, (or both) will provide this to slow down the exiting gases.
And continuing my post from last nite, after 8 hrs of unattended operation, my 513 was still burning bright this morning, even tho the grates were clogged solid. The draft dropped a fraction to .05, so opening the Mpd slighty and closing the intake a tad seemed to be the ticket.
(Wow, must post # just hit 421. An "infamous" Pontiac engine number. I like it)