Low Pressure Weather System and Out Fires?

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Kungur
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Post Mon. Sep. 02, 2013 7:45 am

This past month I have had more out fires than the past 2 Summers combined. It seems that we are having some long spells of humid weather, low pressure system. And this is when I have a out fire.
My guess is the low pressure "kills" the draft.
Anyone else experiencing this?

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Wiz
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Post Mon. Sep. 02, 2013 8:17 am

Only time I was having issues with out fires is during several days of high humid days. Had to add pins to timer and open secondary blower wide open. Getting more unburnt coal during humid days too. Cooler weather is coming ;)
Randy
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Lightning
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Post Mon. Sep. 02, 2013 11:08 am

Kungur wrote:This past month I have had more out fires than the past 2 Summers combined. It seems that we are having some long spells of humid weather, low pressure system. And this is when I have a out fire.
My guess is the low pressure "kills" the draft.
Anyone else experiencing this?
Low and high pressure systems influence draft, not because of their "pressure" per say but because of other factors such as temperature and humidity. Probably more temperature than the other variables.

Chimney draft is a natural occurrence based on differences between the air temperature outside and the temperature of the flue gases. As temperature rises outside the gap closes between these two variables and draft decreases. But I'm sure you know this part :D

It would make sense that atmospheric pressure influences IF pressure in the house remained constant. But we know this can't be the case since opening doors and windows would keep inside and outside pressure equal.

Hypothetically speaking though if you could keep pressure in the house constant, a low pressure weather system would actually increase draft since there would be a higher pressure in the house. And we know high pressure always flows towards a low pressure.

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Rob R.
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Post Mon. Sep. 02, 2013 12:19 pm

Kungur wrote:My guess is the low pressure "kills" the draft.
Yes. Hot & humid days are draft killers. Worse yet is when you have a cool night and it quickly gets hot in the morning...the chimney may be cooler than the outside temperature and it will sometimes reverse.

You may have to increase the timer duration on your Ka-2.


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Lightning
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Post Mon. Sep. 02, 2013 1:34 pm

Pardon my confusion partner but you answered his question with yes but then went on to demonstrate that temp and humidity influence drafting. Are you saying that low pressure areas are associated with warmth and humidity? I would agree with that :D

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Rob R.
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Post Mon. Sep. 02, 2013 1:51 pm

Low pressure, heat, and humidity...any combination of those will reduce draft or at least make the boiler operator uncomfortable. :P

steveyrock
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Post Mon. Sep. 16, 2013 7:27 am

I was having the same draft issues on very hot still days until I introduced outside air directly into the combustion fan.The house was closed up tight with the air conditioning running and that would reduce my draft and I could see it on the manometer.

I ran two inch PVC to the outside of the basement with a 90 elbow turned down at the outside end to keep rain out.There is a mesh screen in front to keep bugs ect out.I then put a 4inch to 2inch PVC reducer right up against the squirrel cage intake of the combustion fan.I didn't glue any of the fittings so it easily comes apart when needed.This completely stopped any hot day draft issues and I haven't had a CO alarm go off since.I run the outside piped air all year long because that combustion fan is going to pull air in any crack avialable and exuast it out the chimney.
get your supply early and avoid future regrets

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Lightning
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Post Mon. Sep. 16, 2013 7:41 am

Well done partner :)


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Rob R.
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Post Mon. Sep. 16, 2013 9:09 am

I did something similar with 4" PVC, but I just ran a "drop" down to about 12" off the floor in a far corner of the basement. It is amazing how much air gets pulled through it when the chimney is pulling hard.

steveyrock
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Post Mon. Sep. 16, 2013 11:44 am

Yes Rob, when I put my hand over my pipe outside and can feel the suction that little fan produces. I wonder how many times a day it would exchange the entire house air if it was not able to get it directly from the pipe. Imagine all the cold air it would be pulling in to the house in dead winter,such as under exterior doors,along sides of window ect. I believe direct and deliberate cold air introduction saves heat and cuts down on drafts in the living area of the home.
get your supply early and avoid future regrets

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Sting
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Post Tue. Sep. 17, 2013 7:15 pm

steveyrock wrote:I was having the same draft issues on very hot still days until I introduced outside air directly into the combustion fan.The house was closed up tight with the air conditioning running and that would reduce my draft and I could see it on the manometer.

I ran two inch PVC to the outside of the basement with a 90 elbow turned down at the outside end to keep rain out.There is a mesh screen in front to keep bugs ect out.I then put a 4inch to 2inch PVC reducer right up against the squirrel cage intake of the combustion fan.I didn't glue any of the fittings so it easily comes apart when needed.This completely stopped any hot day draft issues and I haven't had a CO alarm go off since.I run the outside piped air all year long because that combustion fan is going to pull air in any crack avialable and exuast it out the chimney.
Make up air like this should be on all appliances
When you turn your boiler on -Does it return the favor?
I have finally lost my mind. Don't bother to return it. It wasn't working properly anyway!

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