Draft Issues

[Blevesque]

So here is a little background. I installed a new yorker wc-130 in our new house last november. I burnt 2 or so cords through it with no storage, things were ok. The boiler would heat up to temp in about 45 min then the fan would shut off and smolder and bump off the high limit. So of course I had creosote issues. So I decided to finish the heating season on oil. This summer I was able to pick up 2 200 Gallon ASME Tanks. I finally got around to installing them last week and last night I filled them up and lit a fire at 7:30 water was at 50 Deg. I kept checking on it now and then. I went down at 10:30 to find a nice bed of coals and the water temp up to 120 Deg. So I added more wood, after about five minutes the barometric was completly open and I could see the flames in the flue pipe. I closed the inlet to the fan down to about 1/2" open (was 3/4" to 1" open ) and it slowed down. But man was it sucking air through the barometric. The chimney is 8 x 8 and 45' tall. I'm going to bring a bachrack kit home tonight and get and actual reading. We check it last year when we put it in but when we did it the boiler was only 30-40 min into firing and the stack temp was 350-400. Any ideas! I did clean the boiler and flue this summer also. Thanks

 

[Eric Johnson]

The issue of using a barometric damper on a wood-fired boiler has been discussed and debated here from time to time, I think with inconclusive results. Personally, I wouldn't hook a baro damper up to a wood-fired boiler, especially not a conventional one. A gasifier might be a different story, though I don't have one on my gasser, either. When I had a conventional wood-fired boiler (Marathon Logwood), I just used a cheap cast iron stove pipe damper to regulate the draft. I don't think I could have got by without it, especially not on really cold nights. The boiler is just not designed for unrestricted draft, IMO, and you run the very real risk of a chimney fire if you have flames extending into the flue.

The nice thing about a cast iron damper is that it's cheap, easy to install, and easy to bypass just by leaving it open. You'd be surprised how much wood it will save you in cold weather, too, since it limits the amount of heat going up the stack. Or should I say, it limits the speed at which your heat goes up the stack.

 

[Blevesque]

Thanks for the quick reply. Any ideas as to what I should do about the fan? I see your old logwood had the non-electric damper.

 

[Eric Johnson]

Yes, the Logwood had the Ammark bimetal damper control. I liked it, but when it's wide open and your boiler is full of wood, you'll melt your chimney before the boiler water temp gets high enough to close the damper. Hence the need for a damper.

I've also owned and operated a wood-fired furnace with a draft fan and another conventional wood-fired boiler (Royall), both of which had dampers installed in the chimney. So it works with a fan. Basically, it just cuts the draft. You know that it's closed too far for conditions when you start to smell smoke. There's nothing automatic about a cast-iron damper, of course, but I've found that most "automatic" controls need frequent attention on wood-burning appliances in any event.

 

[Blevesque]

Thanks Eric, I'll pick up a damper and give it a try. I really wish I would have bought a tarm, but at that point of the construction we needed to start cutting things out of the budget. If I had to do it again wife would have laminate counter-tops and a gasifier would be in the basement.

 

[Blevesque]

Got the damper installed and it seems to have done the trick. Thanks Eric!