Changing 90 elbow to two 45's

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rudysmallfry

Minister of Fire
Hearth Supporter
Nov 29, 2005
617
Milford, CT
With just basic math two 45 degree elbows would make 90...but, in the case of smoke and draft, would it benefit me to make a change to my existing installation?

Free standing wood stove. Single wall pipe straight up 3', 90 degree elbow, another 3' straight to outside connector. Currently my draft is okay, but I do am having trouble keeping my stack above 250, and worry big time about creosote buildup in my little, cheap, single wall pipe. (that's getting replaced with double wall next year, but not in the budget for now). Anyway, as the smoke flows, would it increase the draft at all if I came out of the stove at a 45 degree angle, straight for about 3', and then another 45 degree to get it to the outside connector? I don't want to have to extend my chimney higher if I can help it since it already towers over the house and would probably need lines to hold it in place. If I can acheive the equivalent of another foot, that might help my draft situation substantially. Would things flow better this way? I'm thinking the 3' less of pipe alone might do it no less the harsh right angle.

On another note, I called a chimney sweep hoping to get some insight into my various problems. I asked him whether enclosing my completely exterior class A chimney would help my situation regarding burn times, draft, and stack temperature. He said that class A chimneys are more than adequately insulated and I would be wasting my money to enclose it. I know that, in a previous post, that someone here said that I enclosing my chimney could help hold the heat up to 80 percent better. It's got me confused. If there's any hard fact, web sites to document such, I'd really like to get to the cold hard facts.
 
If you have the common adjustiable elbow you would only need one more adjustiable one to twist the angles to a straighten your path
Two 45 still equals 90 degrees turn but it could lessen the effect and friction of the 90. How much I cannot say. For about $5 for another elbow it might be worth experimenting with.

Gardenweb read the tool shed concerning ellectric splitters. I posted a few articles there concerning them and a woodstove primer for new buyers

there are two type od stainless steel outside chimneys cheap air space insulated one and more expensive insulation packed one The insulation packed one is better at retaining heat and would not benifit as much from being in a chase. Air space insulated one would benifit some in an insulated chase. what you would have to factor is the chase cheaper to construct than replacing sir space with packed insulated chimney pipe I do not have the cost answer. I do know changing the pipe is probably easier
 
I checked with my installer. I do have the heavier blanketed insulation packed chimneys. He said in CT, it normally never gets cold enough to make it necessary to require a chase which backs up what the chimney sweep said.

I just need to find a way to get this puppy operating better. While this is a new stove and new setup, I am not new to wood burning. I've been using the older cast iron stove for a good 20 years in many different houses with many different setups. I have never had this problem of stack temperature. I'm still not sure this is even a draft issue. I get very little to no smoke with my fires, and the wood burns to coals very quickly. I have nowhere near the burn time that other people speak of. I stopped adding to my fire at 10:00 last night, and by 1:00 it was ice cold, soapstone and all. Part of the problem may be that I have been only keeping the firebox about half full and only adding two logs at most when the previous load burns to coals. I find I am adding those 2 pieces every half hour. I get that the stack will not ready nearly as hot with a bed of hot coals, as it will with flames dancing on the top of the firebox. Maybe everything's working just fine, and I've just become a tad paranoid where fire's concerned. It took me a month before I'd even leave the house with a fire going, and even then it was almost down to coals. I'll feel better when I take it all apart in the spring and see a nice clean flue instead of 3"s of creosote lining the walls. That's what's really bugging me. The soapstone's a nice toasty 450 degrees. The stack is messing with my head. I'll trying messing with the angle and see if I get any different results.
 
Maybe too much draft? Or your thermometer could be bad? Those cheap magnetic thermometers are'nt the most accurate things. Buy a probe thermometer for your pipe.

Maybe you are paranoid, try filling the firebox full after you have a good bed of coals and running full blast for about 30 to 45 minutes. Then turn down the air, you should have a good long burn over 6 hrs if you use descent hardwood. And the soapstone should stay hot even longer.
 
I thought maybe the thermometer was bad, but I have two of the same. When I switch them, I still get the same uneven readings between the stove top and stack.

Anyway, I got sick of being paranoid. I took apart the stove pipe to take a peek inside. Now I might be paranoid, but I think I've seen less creosote after a single season of burning than I see in these pipes. The creosote in the pipe from the stove to the elbow is heaviest by far, the upside of the elbow is heavier than where it meets the lateral pipe, and the lateral pipe is the cleanest. I'm thinking a smoother angle to the wall would benefit me after seeing this. What bothers me is, this stove has only been used 8 times for about 5 hours each time. Isn't this a lot of creosote for a stove that has been used so little?

I did some further research which suggests double wall pipe holds stack temps better. I guess that's a no brainer since it's insulated. But I just want to make sure I'm addressing the right problems.
 

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I just cleaned my pipes last weekend after about 1 1/2 cords burned, and my pipes looked similar to yours.

What kind of wood are you burning? How old and where is the wood stored?
 
I'm burning what I was told are mixed hardwoods. Some of the logs are much heavier than others. I'm thinking I've got about 70% oak, and the rest is Maple, Cedar and some fruit trees. It seems to be seasoned alright. Only a few of the pieces have popped or hissed. All of it seems to burn quickly except some of the heavier oaks.

I've never cleaned stovepipe before. I know to go through it with a wire brush a few times and get the obvious creosote out. Is there anything else I need to be doing? Also, I cannot do the chimney myself since I don't have a ladder. Can I assume that there's not as much buildup in the chimney since it seems to accumulate nearest to the stove exit and get thin near the exit to the outside chimney? Can I just do the stovepipe and leave the chimney for now? Is this a lot of buildup?
 
Sorry Todd. I didn't answer half your question. I have the wood stacked on wooden pallets. It gets sun until about 2:00. I cover just the top of the piles with tarps when wet weather's coming. I have the stuff that I plan on using this year stacked criss cross. The other stuff is stacked in a more compact way all facing the same direction. I have slowly starting splitting the wood to smaller splits and have been weeding out anything that doesn't appear to be adequately seasoned. Hopefully once I get the stack modified to a straighter line, it will stay warmer, and I won't get such severe buildup.
 
rudysmallfry said:
I'm burning what I was told are mixed hardwoods. Some of the logs are much heavier than others. I'm thinking I've got about 70% oak, and the rest is Maple, Cedar and some fruit trees. It seems to be seasoned alright. Only a few of the pieces have popped or hissed. All of it seems to burn quickly except some of the heavier oaks.

I've never cleaned stovepipe before. I know to go through it with a wire brush a few times and get the obvious creosote out. Is there anything else I need to be doing? Also, I cannot do the chimney myself since I don't have a ladder. Can I assume that there's not as much buildup in the chimney since it seems to accumulate nearest to the stove exit and get thin near the exit to the outside chimney? Can I just do the stovepipe and leave the chimney for now? Is this a lot of buildup?


When I clean mine all I do is run a brush down a few times and then disconnect the pipe and brush that out. Usually the liner has more creosote build up than the stove pipe because it gets cooler the further away from the stove. I had the shiny hard creosote at the very top and a little crusty brown stuff similar to yours in the stove pipe. Get a ladder and check the top of your liner, run a brush down, and see what comes out at the bottom.

By the looks of your pipe I would think there is little chance of a chimney fire. That stuff would probably disappear from a hot fire. If it continues to build up and reduce the diameter then you need to be paranoid. My first stove was an old Montgomery Wards barrel stove. I use to burn wet wood until I saw black goo dripping from my pipe seams. Then I checked the 8x8 chimney and there was about a 3" diameter hole, the rest was creosote! I was lucky I didn't burn the house down! That scared me into making sure my firewood is dry and chimney was cleaned.

Have you tried loading up your firebox and burning hot? The stack temp should shoot up to 600 in about 30 min. That's when I turn my air down and the stack temp will drop into the 300 to 500 range. The stove temp takes awhile to catch up, but after an hour it will be up to around 500. I found my stove operates best with a full load.
 
Thanks Todd. Once I get everything cleaned out, I'll try the hotter fire. We've got a virtual heat wave going this week in CT, (55 degrees out today) so I took advantage and re-split my wood pile into smaller pieces. I put my two year old Maple supply front and center. It's bright white on the inside, can't get any drier than that. The rest of the stuff fell apart easily except for one species that repelled my maul like it was steel. If it wasn't completely dry before, it should be much better after a nice warm week in the sun.

Just a few more questions, and then I'll stop bugging you. I'm going to switch my stove pipe double wall at 45 degree angles to soften the path to the chimney and keep the temp up. My manual shows a clearance requirement for X' from center of stove pipe to wall. If I slant the pipe, what should I consider to be center?

Also, I don't have access to a ladder, and am not a really big fan of heights. Can I get an adequate look at what's going on in my chimney by looking up from below? I don't anticipate much if any buildup since there is very little on the stove pipe going to the chimney. All of my buildup appears to be right out of the stove.

One more stupid question. There doesn't seem to be any good step by step instructions on the web about cleaning stove pipe. I know to take the sections off, take them outside and wire brush out the creosote. Is there anything I need to do at the stove itself while the pipe is out of the hole?

thanks again.
 
By installing your 45's does that bring your pipe closer to your back wall? I think you have to measure from the closest point your pipe is to the wall? How tall is your chimney? Those 90"s reduce the overall hieght 5' each. I think the Homestead requires a 13' chimney. Mine is a outside brick 22' chimney, and has 2 90's. So I figure 12' after subtracting the 2 90's. But my draft is fantastic. Maybe you should keep it with the 90's for awhile until you get use to the stove? It took me a full season to learn all the perks and tricks of this stove, and I'm still learning. It doesn't hurt any to take the pipe apart and inspect it once a month or sooner for piece of mind.

I use to look up my chimney using a mirror before I installed a liner. You should be able to see the light at the end of the tunnel if you have a straight chimney. Do you know anyone who would go up there and take a look. Offer them a beer or two AFTER they go up there.

I use single wall pipe and all I do is inspect for rust and wire brush it out. I've had the same pipe for 3 years and looks good as new. At only a few bucks a section it won't cost much to replace. After I clean out my stove pipe I look into the stove from the exhaust and inspect the top of the baffle. There may be some fly ash building up after awhile, so I vaccume or brush it out.
 
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