Another new guy

[rawheels]

I just restored an old farm house that my grandparents lived in. I constantly talked about the old woodstove that my grandparents had on the back porch (which had somehow walked off WITH it's chimney while the home was vacant), so my family bought me a new stove for Christmas. It is a US Stove King 2007. I installed it with a new DuraPlus triwall chimney kit from Simpson DuraVent. I'm having two problems;

#1 There is a ton of smoke spillage when I open the door. The wind came from a different direction the other day and I tried it again with a little more success, but even with a windward window cracked and opening the door slowly, I still get smoke billowing out whenever I open the door. (We haven't had a no wind day yet to try it) I've considered purchaing a Vacu-Stack in order to increase the draft so it will suck the smoke up the chimney, but that would be contrary to my other problem which is too much incoming air:

#2 With the door open the fire burns pretty nice (except for the smoke coming in the room), but as soon as the door is shut the wind from the inlet above the door seems like it is really coming in fast. When the fire gets very large the flames and smoke go up then towards the door and then the air coming in sends it downward, so it just rolls and rolls in there. And there are no controls to limit the incoming air.

Any thoughts?

Ryan

 

[cmonSTART]

Does your chimney go straight up? Or does it go through the wall and up the outside of the house? How tall is it? How High above the roof?

 

[rawheels]

Goes pretty much strait up. The stovepipe has two 15 deg elbows with about a foot of pipe in the run to offset a couple of inches so that it lines up with the chimney box. 9' room, so about 7' of stovepipe to the box, then 6' of triwall chimney pipe (Approx 3-4' above roof). It is on a single story porch connected to a two story house. So there might be some wind loading, but there was never any draft problems with the old stove. I don't know how far above the roof the old chimney was, but it was pretty short, definitly not above the second story height.

Ryan

 

[swestall]

Sure sounds like weak draft. A sure fire way to know is to call a local sweep or dealer that has a draft meter and have it tested. The fix will be obvious from there.

 

[Todd]

How dry is your firewood?

 

[Corie]

You didn't mention, so I'm not sure you realize that you purchased a 35:1 exempt wood burning unit. This type of stove generally, by design, does not have air controls as the burn rate is not user controlled. Do a search on 35:1 or exempt wood stoves to find out a little bit more info.

The long and short of it is, you purchased a fairly poor home heating unit. No offense and I hope you don't take it the wrong way, but 35:1 stoves generally do not make good heaters. Without a secondary combustion system or air control, you're going to send a lot of heat and efficiency points up the stack.

It ALSO sounds like you have weak draft. Did you follow the 10-3-2 rule when installing the stack?

 

[cmonSTART]

No offense and I hope you don't take it the wrong way, but 35:1 stoves generally do not make good heaters.

It's true. Been there. The difference between our previous Englander 35:1 and our new one is night and day.

 

[Hogwildz]

Chimney is too short and those elbows equate it to even shorter length. I know a 90 = 5' deduction in chimney height, what does a 15 & 30 degree =?

 

[stoveguy2esw]

Goes pretty much strait up. The stovepipe has two 15 deg elbows with about a foot of pipe in the run to offset a couple of inches so that it lines up with the chimney box. 9' room, so about 7' of stovepipe to the box, then 6' of triwall chimney pipe (Approx 3-4' above roof). It is on a single story porch connected to a two story house. So there might be some wind loading, but there was never any draft problems with the old stove. I don't know how far above the roof the old chimney was, but it was pretty short, definitly not above the second story height.

Ryan

single story hip roof flues attached to a 2 story main building always present a challenge, even meeting or exceeding the 10-3--2 rule for the lower single story roof can cause serious wind loading when the wind comes over the taller structure. usually this type of flue installation is not recommended due to the issues from the higher roof. ideally the stove would be placed on a wall that borders the two story part of the structure and set the flue at the proper 10-3-2 rule to the higher roof (preferrably enclosed in a chase) this will allow proper draft regardless of wind direction and backdrafting due to wind loading from over the higher roof to a lower flue.

 

[rawheels]

No offense taken on the stove choice. It was purchased for me, so I get to claim no responsibility. Although I wouldn't have known any better if I picked it out myself. Looks like all of the air gets pulled through some slots right above the front door. Could I add a control somehow? Metal tape or magnets? Might look kind of ugly, but would allow me to control the burn rate a little more. I'll deal with the heat issue after I can make some successful fires without smoking out the house.

Yes, I did follow the 10-3-2 rule. Chimney is between 3-4 feet above the roof which is very shallow pitched. I did not see any other requirements for chimney length in the install manual.

The porch is on the west side of the house. During the winter, with wind blowing from the northwest, I shouldn't have any problem with wind coming down from the second story. The windload I would have a problem with is the high pressure zone created by the air hitting the side of the two story section.

I'll pick up a Vacu-Stack and see if it alleviates any of the problems.

Ryan

 

[rawheels]

So, I took a look at the install manual online. Owners Manual. Looks like it says 11' chimney minimum. I don't see anything about how to calculate in elbows, but on another unit it says 12' min or 16' min with 2x90 deg or 4x45 deg elbows. So, since you can use two 90's or four 45's I assume I can safely assume I could guesstimate my effective height loss as 2' or less, correct? If my height is 13' - 2', I am right at minimum 11' height. Would another 2' section of triwall chimney pipe really create that much extra draft?

Ryan

 

[SlyFerret]

From what I've learned and read, yeah, it can.

I'm going to have a pair of 30 degree elbows in my chimney to offset slightly in order to miss the peak of my roof. I'm hoping that I don't have to add a bunch of height to it to make it draft right. My roof is only about a 3.5 pitch or so, and a really tall chimney might look a little goofy. Either way, I'll trade goofy on the outside for comfy on the inside. Besides, when I'm inside, I won't be able to see the chimney outside anyway!

-SF

 

[Jags]

So, I took a look at the install manual online. Owners Manual. Looks like it says 11' chimney minimum. I don't see anything about how to calculate in elbows, but on another unit it says 12' min or 16' min with 2x90 deg or 4x45 deg elbows. So, since you can use two 90's or four 45's I assume I can safely assume I could guesstimate my effective height loss as 2' or less, correct? If my height is 13' - 2', I am right at minimum 11' height. Would another 2' section of triwall chimney pipe really create that much extra draft?

Ryan

Short answer - Yes.

7 years ago, with my new stove and stack install I would get a backdraft situation about 1 time every 2 months (wind, weather, etc.). I added a 2 ft section to the top of the stack and it has NEVER happened since. That being said, I think that you may also be dealing with the 35:1 stove issues that come with the territory.

 

[rawheels]

Amazing, it worked:
Yesterday was the first time since my chimney install that there was very little wind around my house, so I lit a kindling fire to see if I still had smoke spillage. I did, which means the vacu-stack wouldn't be the permanent fix. So, I went and picked up another 3' section of chimney pipe. I just removed the cap and set the tube in place without anchoring it down. It was a dramatic difference. Before when I opened the door the smoke would just billow out the front, with the extra 3' I could actually see all of the smoke rushing to the back of the stove when I opened the door. There was a very very tiny amount that still came out, but I'm sure that is just from either the small kindling fire or the bad design of the stove. I don't understand the physics of why additional pipe creates more draft, but it worked for me. THANKS FOR THE HELP.

Now I've got another question: Since I will now be 4' above my roof I will need to use bracing straps. The local store does not carry the DuraVent/DuraPlus brand extended roof bracket kit. I can order it online from a few places for about $40+S/H. Is that the best route to go, or am I wasting my money? Outside diameter of the triwall is around 10", is there a list of items I could just get from a local home improvement store that would be equivalent to the kit?

 

[swestall]

Someone once said, "Better Safe than Sorry".....

 

[Jags]

Ryan, glad to hear your stove is drafting better. My suggestion would be to order the kit that belongs to your stack, but thats me. 40 bucks ain't a whole lot when spread over the years of service you can expect out of your stack. Make it right.

 

[rawheels]

Not trying to skimp. It just looks like a band clamp with two angle brackets ( seen here ). I even have to go buy some tubing in order to install it, so I thought maybe it was one of those "hey if some idiot is willing to pay for it" items. Thanks again for the help.

 

[SlyFerret]

I can't speak for the DuraVent that you used, but in the manual for the SuperVent that I used, it states that the support bracket is required if the chimney extends more than 5 feet above the roof deck. If it were my stuff, at 4 feet, I would be safe according to the manual, but I would check to see how stable it was and use a bracket accordingly.

-SF

 

[rawheels]

Thanks Sly, The DuraPlus requires supports above 4'. I had a stack just under 4' to begin with so after I add the extra 3', I'll be way above the requirement. Thanks though. Ordered the kit online, should have it Monday.

 

[Jags]

Looks like you are well on your way to a happy wood burner. Keep us posted on the performance of that stove, now that you have it dialed in. It will most likely take awhile before you figure out what the stove wants to optimize it performance, but that will come with time and many loads of fuel.