Question about low draft

I'm having a problem with not enough draft I believe. I have a Lopi Answer woodstove. When I run the woodstove, commonly I can smell smoke in the basement coming through the cleanout, sometimes there is a haze from so much smoke. I have a friend with experience with woodstoves and he says mine is much more difficult to start than his and there is definitely less draft compared to his. Also, sometimes if I don't get the fire going right at the beginning, smoke will billow out of the intake of the stove. I always put a couple of pieces of paper in the flue and light it to preheat the flue, this helps a little.

I have a masonry chimney, flue size inside dimension measures 6 3/4 x 6 3/4 square, flue length is roughly 20' + 6' of pipe going to the wall from the stove.

I bought a 6" stainless liner recently thinking that my flue was too large. Once I actually looked at the flue and saw that it was 6 3/4, now I'm questioning if putting in this liner is going to make any difference.

Is it worth putting in this 6" stainless liner? It should just barely fit according do my measurements? 6" is the recommended size for this woodstove.

Thanks in advance for any thoughts.

BeGreen said:

Welcome, love your handle. There must be an interesting story connected with that.

Is this an exterior chimney? They can be touchy, especially when it's not very cold outside. The flue pipe doesn't sound like the main issue. One thing you might try is sealing the cleanout tightly. If the cleanout door leaks air, it could be affecting draft. As a temporary test, take some wide tape like duct tape and seal it up. If that helps, seal it up with a healthy bead of silicone.

How is the stove connected now? Can you describe the connecting pipe setup? Is there an elbow above the stove? If yes, is there a section of horiz. pipe after the elbow? That needs to be pitched uphill at least 1/4" per foot.

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It is an exterior chimney. I have connected the stove with a 3' vertical 6" pipe, then a 90 deg elbow, then connecting into a 21" double insulated pipe that goes into the wall fitting nice and snug into an 8" round masonry flue connection. I never bothered to seal it in, I figure it's best to leave it so I can remove it for cleaning. The 21" horizontal pipe is pitched just over 1/4" per foot.

I'll try putting the tape on the cleanout and see if that helps.

Thanks for all the responses!

Guardguy said:

There has been some good advice so far in this thread, I will try to add to it.
You probably have a combination of problems. I assume this is your first season with the stove. I also had problems in the past with a Lopi Answer. It was an insert connected to a short exterior chimney.
Here is a list of some potential causes, some already covered.

1. Too warm outside to create a good draft.
2. Tight house. Outdoor air connection would help this.
3. Air leaks near the top of the house. Make sure your attic access is sealed well.

Another suggestion: turn off all exhaust fans and clothes dryer until the fire has heated up the chimney. I use to crack the front door if the dryer was running when I started a fire.

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This is actually my third season with this stove, I've dealt with this problem over the last years. I've been living with it, but my friend insists I need more draft. I built my 1600 sq foot Cape house myself four years ago doing most of the work myself. I have 2x6 walls, everything is overinsulated and wrapped tight. My attic access is a 24x 30" opening with a piece of plywood at the top of the stairs, with overlapping r30 insulation criss crossed to seal it tight. I have tried opening a window or door to see if that helps the draft in the past, it doesn't seem to make it any easier to start a fire.

Should my stove be as easy to start as my friend with an insert that has a 6" stainless flue liner with an insulated blanket?
I have no trouble starting his fire. He was unsuccessful in starting mine.

Even when a fire is roaring, there doesn't appear to be near as much draft that I can feel with the door cracked open as I would expect would be normal.

One last note, this stove is an older one that I bought used that was manufactured in 1984. I'm just adding that info in case it makes any difference.

Thanks everyone for your help!

BeGreen said:

Have you tried opening a window a couple inches, close by the stove? Also, when testing using the open window, be sure that no fans (bath, whole house, ventilator, clothes dryer, kitchen, etc.) are running. If that makes an appreciable difference you may be wanting to consider getting a more modern stove that can accommodate an outside air kit.

If that makes no difference, then looks closely at the flue cap to be sure it's not clogged. Draft may also be improved by redoing the connector pipe with a 45 on the stove, then diagonal pipe, then another 45 at the chimney connection.

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I have a window about 8 feet from the stove that I have tried opening and it does not seem to make a huge difference in getting a fire going, no fans are running when I do this test. This is a test I've done during the winter when it's colder outside, it is too warm outside right now to do a test right now.

I don't believe a 45 would work in this situation without installing a fireproof wall behind it. The stove is 16" from the drywall in the back, which is the recommended distance minimum.

Is it possible that the flue cap I have installed could effect the draft? It is a big one covering 2 flues and is roughly 8 inches in height if I remember correctly.

I'm still considering the stainless liner. Today I went on top of the chimney and put the T down the furnace flue (because it's cleaner) with a wire and it easily went down five feet with no trouble. I think I can get the whole liner down without too much trouble if I clean the woodstove flue really well. I'm going to try everyones suggestions first though. I got a great deal on the liner several weeks ago. The Stainless liner kit was $315 for a 25' kit with T and Cap. I guess I jumped the gun a little buying this liner, oh well.

Thanks for all the replies!

BeGreen said:

If you use double wall fittings and pipe the clearance will be ok. Using double wall will also help the draft by keeping the flue gases hotter.

By the description the flue cap doesn't have a screen, so that is not the issue. Have you considered putting an extension on that flue?

Click to expand...

The cap is rectangular and has 1" openings around all sides to keep the squirels and birds out, there is no mesh screen.

How tall would the extension be? The flue is 2' over the peak of the roof.

That looks just like mine, only I don't have the blower or the brass door. Nice stove!