Draft in Milder Temps?

Dennis, I fully intend to do just that, but for right now I just have to deal with what I have. Also, the manual for this boiler states the chimney must be capable of a draft of at least.06; But nowhere does it state recommended draft for the unit. In this case I'm trying to maintain .06, but still not sure if this is correct. And I do seem to be using a fair amount of coal.

Does your furnace have a thermostat controlled primary combustion air? If not, you are a perfect candidate for a barometric damper. It will limit your draft and make for steady heat output.

[quote="J F Graham"]Dennis, I fully intend to do just that, but for right now I just have to deal with what I have. Also, the manual for this boiler states the chimney must be capable of a draft of at least.06; But nowhere does it state recommended draft for the unit. In this case I'm trying to maintain .06, but still not sure if this is correct. And I do seem to be using a fair amount of coal.[/quote]

I apologize for not being specific in my first post. I should have come right out and asked how much coal are you burning, but not being a "boiler guy" I stuck to the topic, "draft........" and I didn't want to turn this into a mpd, baro thread either. I wish you well friend and hope any issues get resolved.....at -.03 to -.05 is my sweet spot.
Mike.

Once again, we'll all admit each installation is unique. But it is amazing how much difference a few points in draft will affect performance. With-out my baro, my draft ran -06-07, and by dropping it down to -.04, made a marketable difference in performance. I'ld like to know how many members stoves perform well at a -.1 draft. Is this extremely high/hot, or not for all stoves? Maybe the larger stokers or furnaces operate up there?

In general, -.03 to -.05 is a good operating range for most all coal appliances.

With an air tight stove where there is complete control of primary and secondary air input, a stronger draft (-.1) wouldn't have impact on efficiency. I'm sure some would disagree. ..

Trouble is, a chimney probably won't always draft this strong so it wouldn't be wise to use for a normal operating pressure.

Guys, I fully realize that a baro "NEEDS" to be installed, and will be after this season. And yes this unit does have an aqua stat controlled primary. Sorry for the confusion about the wood; all I was saying that by generating excessive draft, the extra turbulence, especially in the smoke chamber might remove some fly ash. So far it seems to work, and in my case certainly can't hurt. I'll know in spring. As for mano readings, at an idle about .04, and .06 when primary is open. The low port is attached to the stovepipe. If anyone feels that these numbers are not in order, please let me know. As far as consumption, during last cold snap about 75 lbs per day; normally 60-65. Any suggestions appreciated.

I'd say yer good ..

Thank you, everybody.
Jim

First God Bless You for milder temps...it's -3 here today in SW Michigan 30 miles from the Big Lake. I don't know what milder temps are anymore.

If you keep burning wood with coal you can get a chimney fire and cause a lot of damage. I'd pass on being unconventional and take the advice of the people here and remove the pipe and clean, or get a chimney sweep, or realize that different days weather will effect draft.

Bpatrick, Don't feel too bad about the temps, I hear they are headed this way . I much appreciate your concern, and will shut down and clean if necessary. However, all readings on the boiler, stack, mano ect now indicate all is well. Stay warm my friend.

Great news and happy burning. On warm days, my stoves can almost roast me out of the house so I like to get fresh air by having to open a few windows. they've been closed for so long and I like to get it warmer in the house and open the windows a little bit. Mentally, it makes me feel like spring and I like the fresh air. Not for too long but a few hours of fresh air in the house is a great feeling.

When it comes to draft in all conditions, the only thing that really matters is the height of the stack above the neutral pressure plane in the house - easiest way to go about this is to make sure your stack is at least a few feet higher than the highest part of the roof of your home - the higher the better.

Gentlemen, glad to hear a positive reply!! My stack is at least 22 ft above thimble, and at least 2 ft above ridge. So I have a very strong draft. Now bearing this in mind; on this particular unit, there is a " smoke chamber" right behind the flue exhaust. It is a boxed in area the width of the unit, with two entry ports on opposing sides, and on the bottom. Harman describes this as their " Spiral flue". Hence SF 160. Where gasses are "supposedly" entered and spiral around, expending the last of their energy. What a perfect area for ash to settle. Now, also bearing mind that this unit is a " duel fuel" and wood is also an option. As the " numbers" started to decline I began thinking how to vacate the possible ash, without a shutdown. Having burnt wood for 40 yrs, and I don't mean recreationally, I decided on a "Wood fired Enema". to see if an extremely strong draft, might turn my chimney into a shop vac on steroids. All I can say is; "The bed pan is full", and the draft is fine.

My buddy has a combo (wood and coal) stove, and when out for long time away from the burning coals, when he returns to a weak bed, he just throws some logs on it to get it fired up again. What ever works I guess.