Draft ?

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whatisup02

Member
Feb 3, 2012
164
MI
6" black pipe 90 out of furnace the up 24" to a 90 36" class A out the wall to the T then 18' of class A. I don't know much about draft or chimney, so I'm asking does this setup sound good for a good draft? The chimney is about 2' past the p[peak of the roof and the chimney is about 15' from the ppeak.
 
I know on the supervent class a chimney the instructions say a maximum 2' length of horizontal pipe through the wall before the T. Not sure about other brands though.

I dont quite understand what you are saying about the height above the roof. You need to be a minimum of three feet above the shingles AND 2' higher than any point of the building within 10'


Edit

Read what you wrote again, are you saying you are 2' higher than the peak which is 15' away from the chimney?
 
whatisup02 said:
6" black pipe 90 out of furnace the up 24" to a 90 36" class A out the wall to the T then 18' of class A. I don't know much about draft or chimney, so I'm asking does this setup sound good for a good draft? The chimney is about 2' past the p[peak of the roof and the chimney is about 15' from the ppeak.
It doesn't sound like you will get a real strong draft there. What does the furnace require? It seems that the 18' class A is on the side of the house? If so, 2 90's & exposed 18' pipe(not real long for a chimney) probably = less than ideal draft, Randy
 
Thank's for the replys. Is there a cheap way to test draft?
 
I would buy a Magnehelic off Ebay. The one you want is 0 to .250 water colume. Mine cost me about $15.00 including shipping. You will likely pay more now though. You can make one out of tubing & colored water, this wasn't for me though, Randy
 
Singed Eyebrows said:
I would buy a Magnehelic off Ebay. The one you want is 0 to .250 water colume. Mine cost me about $15.00 including shipping. You will likely pay more now though. You can make one out of tubing & colored water, this wasn't for me though, Randy

I bought a Bacharach Draftrite Pocket Version for $99. These things have been around a while and the old timers swear by them. A little pricey but figured it was a good long term investment. Price on the web and you can find good deals.
 
Is it not drafting? Usually .05 H20 is a good number, I too got a Magnehelic from eBay, I like the old school look] , more sections added on top can help increase draft, a lot of times on houses you get weird wind action or a low pressure on one side that can cause a venting issue. Try opening a basement window [assume unit in basement] and see if that helps, if the house is slightly negative [for what ever reason] That will slow down draft or cause it to spill.
 
bigburner said:
Is it not drafting? Usually .05 H20 is a good number, I too got a Magnehelic from eBay, I like the old school look] , more sections added on top can help increase draft, a lot of times on houses you get weird wind action or a low pressure on one side that can cause a venting issue. Try opening a basement window [assume unit in basement] and see if that helps, if the house is slightly negative [for what ever reason] That will slow down draft or cause it to spill.

No spilling. I'm not getting good temps. I can hit 400 but that's with the ash door open. If I close it down for the night it drops to 250 or so. I would like to run it up to 600 or so to help keep the chimney clean. I don't mean run it to 600 and leave it. Just for 15 min or so.
 
taxidermist said:
How seasoned is your wood?

Rob

Not like it should be. I was not planning on burning this year but I got it installed faster then I thought I would. The wood is ash and does not feel cold when I grab it out side. It also lights up fast. I thought that the "greenish" wood might be the problem but it lights so easy.
 
well since its ash you will be a little better as I am sure its been dead for a while.

watch my video and it shows how I measure draft.

Rob
 
Draft measurement.

I see that the manometer is used to measure draft.

Is it ONLY measured when the device is operating? Or will your chimney have suction thru it just from a passing breeze?

JP
 
KenLockett said:
Singed Eyebrows said:
I would buy a Magnehelic off Ebay. The one you want is 0 to .250 water colume. Mine cost me about $15.00 including shipping. You will likely pay more now though. You can make one out of tubing & colored water, this wasn't for me though, Randy

I bought a Bacharach Draftrite Pocket Version for $99. These things have been around a while and the old timers swear by them. A little pricey but figured it was a good long term investment. Price on the web and you can find good deals.
I used one of those & they are nice! I borrowed one & unfortunatly I had to return it, Randy
 
mikefrommaine said:
I know on the supervent class a chimney the instructions say a maximum 2' length of horizontal pipe through the wall before the T. Not sure about other brands though.

Sometimes I feel like my brain is going to explode trying to figure all this stuff out. The setup I'm going to do sounds similar except I'll have about 33' of chimney. However, the boiler I'm looking at says I need 21'' of clearance behind the appliance. So, I'll use up most of that 2' before I even get to the wall... What am I doing wrong?
 
We burned a furnace like yours for years before buying a different furnace. You will have to play with the air based on your heat requirements and fuel quality. If you want higher flue temps, you will need more air. The problem with that is short burns. The best thing I can tell you is watch the chimney. If you get little to no smoke your doing okay. As far as the chimney height or draft is concerned, it should be fine. 2 90's is like removing 8 feet of chimney from the height. With a simple firebox, if your not getting spillage then I wouldn't worry about draft. Just keep an eye on the flue and chimney, clean as needed.
 
laynes69 said:
We burned a furnace like yours for years before buying a different furnace. You will have to play with the air based on your heat requirements and fuel quality. If you want higher flue temps, you will need more air. The problem with that is short burns. The best thing I can tell you is watch the chimney. If you get little to no smoke your doing okay. As far as the chimney height or draft is concerned, it should be fine. 2 90's is like removing 8 feet of chimney from the height. With a simple firebox, if your not getting spillage then I wouldn't worry about draft. Just keep an eye on the flue and chimney, clean as needed.

Could you get your up to 600?
 
hiker88 said:
Sometimes I feel like my brain is going to explode trying to figure all this stuff out. The setup I'm going to do sounds similar except I'll have about 33' of chimney. However, the boiler I'm looking at says I need 21'' of clearance behind the appliance. So, I'll use up most of that 2' before I even get to the wall... What am I doing wrong?

I think I have it figured out now. I don't want to hijack this thread so all set.
 
JP11 said:
Draft measurement.

I see that the manometer is used to measure draft.

Is it ONLY measured when the device is operating? Or will your chimney have suction thru it just from a passing breeze?

JP

Both.

Rob
 
I didnt have a flue thermometer at the time. I would monitor the chimney for smoke and try to keep enough air for a clean burn. I still ended up with alot of creosote when I would sweep. Remember if taking external temps, 300 degrees would be around 550-600 internal on single wall pipe.
 
laynes69 said:
I didnt have a flue thermometer at the time. I would monitor the chimney for smoke and try to keep enough air for a clean burn. I still ended up with alot of creosote when I would sweep. Remember if taking external temps, 300 degrees would be around 550-600 internal on single wall pipe.

I did not know that. I thought that was only on class A. So if I keep it at say 250-300 I'm good to go? I know I still have to keep an eye on the chimney for creosote.. will it hurt it if I run it up to 600 or so for 10-15 min?
 
Is using a damper on a flue of a wood boiler typical or it it just used if you have draft problems?
 
Sparky said:
Is using a damper on a flue of a wood boiler typical or it it just used if you have draft problems?

Well they run the best at a set draft and the only way t do that is with a BD

I explain it like this.. Its a nice calm day your boiler is running good, your draft is .05wc now the wind picks up and starts pulling your draft higher say .10wc your boiler setting are set to run the best at .05wc and now the heat is being sucked past the heat exchanger tubes and not transferring the heat to the water. Now your stack temps go up and you are now wasting heat.

With a barometric damper you stay at your set sweet spot when its calm or windy.


Rob
 
Thanks Rob, I see yours is at the bottom of the Tee is there a reason you put it there instead of above it?
 
Sparky said:
Thanks Rob, I see yours is at the bottom of the Tee is there a reason you put it there instead of above it?

The only reason i put it there was it would cost a bunch of money for the adapters to place it in the twist lock insulated pipe. It worked out great because it is not in the smoke stream too.


Rob
 
I like that idea and the reasoning, I am going to connect mine the same way. I noticed yesturday (real windy) my fires didn't last long and it wasn't that cold out hopefuly this is the reason why.
 
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