Will Not Burn Coal Well

windyhill4.2 wrote: ↑

Sun. Nov. 12, 2017 7:45 pm

Try a 45* slope on that 4' horizontal run,with it level,the hot air gets into the horizontal & meets cold air & can't figure out which way is up.

This isn't guess work on my part...

This is based on REAL experience from many yrs ago when burning wood.

No, there is no real chimney, the stove pipe just turns upwards and goes above the roof. No masonry or triple wall chimney, just single wall pipe.

That is why you have draft problems.

Can the single wall pipe on the exterior of the house be allowing the exhaust gasses to cool too quickly after leaving the stove? I would think that could kill your draft. The whole idea is to keep those gasses hot so they create the rise and pull more air from beneath. The higher the chimney = more draft.

I think that’s why when the old-timers built a stone fireplace and chimney, it was built out of the biggest fieldstones they could find...once stones are heated and draft established, the huge mass of the heated stones helps to maintain the proper draft.

I found this out quickly years ago on a stoker boiler in a shed. Once I went to double wall insulated pipe, it helped the draft very much. Likely the only thing that kept it going to begin with was the fan running on the stoker.

Would like to see a photo of the flue outside the house...

Missed Robs response as I was typing!

I think we’ve nailed it.

windyhill4.2 wrote: ↑

Mon. Nov. 13, 2017 6:42 am

This isn't guess work on my part...

This is based on REAL experience from many yrs ago when burning wood.

Same here.

Had a 3 foot horizontal run on my small potbelly stove. Getting it to light without back drafting against the house's chimney affect took pre-heating that horizontal section of pipe with a pro-pain torch while the stove dampers were closed. Then once the hot and cold air inside the pipe figured out who's boss, quickly open the primary and light the kindling.

And I was also using single wall pipe outside. That was ok once a wood fire was going, but the single wall pipe lost so much heat and draft strength that running a coal fire slowly got tough to maintain enough draft to keep it from dying.

It's gotta be insulated pipe outside, or stick to burning with a high exhaust heat to maintain a safe draft.

Paul

I have single wall pipe on a small box stove I have in my garage. It works with much added difficulty. After exiting garage , it only sticks up 6 feet. Single wall, in order for me to get it burning really well, I heat the chimney with a piece of newspaper to get draft goin. Once lit , I have a small fan 6” on floor directed at air intake to keep the fire burning hot. I burn only wood and just use to take the chill off when working in there.
I guess what I’m trying to say is, you can make anything burn, may not be very safe though. Follow the advice of these guys and be safe. I hope you can get going good.

NoSmoke wrote: ↑

Mon. Nov. 13, 2017 6:34 am

No, there is no real chimney, the stove pipe just turns upwards and goes above the roof. No masonry or triple wall chimney, just single wall pipe.

Houston...there's a big part of your problem.

With a wood fire, you "might" be able to overcome the single wall as your exhaust gasses are very high....BUT....I wouldn't burn wood in that setup, it's begging for creosote issues and chimney fires take the fun out of everything.

Go triple wall out and up and you should see a big improvement.

He mentioned his chimney pipe totals 17' high, (not counting the 4' horizontal run.) and is 6" diameter. Sounds like plenty of run for drafting, no? Or are you guys saying because it's not "insulated" the outside temperature of the pipe is affecting the draft?

joeq wrote: ↑

Mon. Nov. 13, 2017 1:58 pm

He mentioned his chimney pipe totals 17' high, (not counting the 4' horizontal run.) and is 6" diameter. Sounds like plenty of run for drafting, no? Or are you guys saying because it's not "insulated" the outside temperature of the pipe is affecting the draft?

That's what I think. Seems like the gasses would cool immediately after exiting the house. You could probably have a pipe 30 feet high with the same stove setup and if the gasses are not hot enough it still would not create any "lift".

The double and triple walk pipes has the insulating value to keep the heat in the pipe where it belongs... no immediate cooling effect.

Unless I misunderstand the triple wall pipes are designed to cool the gas to prevent overheating. That third layer is open for circulation through the length of the pipe.

I would only use double wall insulated.

franco b wrote: ↑

Mon. Nov. 13, 2017 3:05 pm

Unless I misunderstand the triple wall pipes are designed to cool the gas to prevent overheating. That third layer is open for circulation through the length of the pipe.

I would only use double wall insulated.

You are correct.

joeq wrote: ↑

Mon. Nov. 13, 2017 1:58 pm

He mentioned his chimney pipe totals 17' high, (not counting the 4' horizontal run.) and is 6" diameter. Sounds like plenty of run for drafting, no? Or are you guys saying because it's not "insulated" the outside temperature of the pipe is affecting the draft?

Too much heat is lost through the outdoors single pipe wall. By the time the exhaust reaches the top there's hardly any pressure difference to give a strong enough draft.

It's kinda like sticking a potato in the tail pipe ! I know that you know what that means.

Paul

Yes Mam, There's your problem. No chimney..........

Sunny Boy wrote: ↑

Mon. Nov. 13, 2017 3:39 pm

It's kinda like sticking a potato in the tail pipe ! I know that you know what that means.

Paul

Good analogy Paul. I'ld prefer a spark plug in the tailpipe.

Oh yeah, I did the stove pipe chimney thing my first year. It was funny cuz while the sun was hitting it in the evening it would draft like mad. Once the sun fell under the hill it struggled to draft at all, that's how touchy it was. It kept things pretty exciting lol.