Draft Help

[garjess]

We bought a new Mansfeld stove two years ago. The chimney and stove pipe were also replaced, As reccommended by the stove store, we have double wall stove pipe ( about 10ft.) and 6 ft of chimney outside. We have the same problem with smoke out the front door that I have read others have. Cold start ups are fine, I have no problem starting a top down fire with no smoke coming out. Once it's time to reload we open the air all the way and crack the door for a little bit. We still almost always have smoke come out the door. I thought originally it was a stove problem but I removed the secondary burn plates in the top of the fire box so it operates like an old stove. With those removed its just a fire box with a chimney on top, and we still got smoke out the front door.

 

[NickW]

Maybe try a quick small hot fire first to re-establish draft before a full reload? Or don't crack the door allowing too much cool air in, only open the air?

 

[stoveliker]

If you have smoke roll out, you may not have enough draft. That can be because the chimney is not tall enough (I note that 16 ft + 2 elbows equates to 14 ft effective height).
(And if you're above 1000 ft elevation, you may need to add another ft of flue height to the minimum recommended heigh of your stove.)

But I don't understand; if it's reload time I don't have any smoke generated as the few coals needed for a reload with dry wood don't create smoke.

So how come you even have smoke when you reload (regardless of whether it goes up the chimney or into the room)?

You can try to add a 3 ft section of stove pipe to the chimney to test if a taller chimney resolves the problem. If it does, you know what to do (add chimney pipe and bracing).

 

[NickW]

I get smoke at reloads until it catches well (with dry wood...), often billowing, even with ash which is notoriously quick lighting. My draft can be a bit suspect if I allow the flue to cool too much.

 

[garjess]

Maybe try a quick small hot fire first to re-establish draft before a full reload? Or don't crack the door allowing too much cool air in, only open the air?

We originally tried just opening the door and putting in wood (like I've done with every other stove I've owned). That didn't work so we then tried opening the air, then I read about cracking the door to let the smoke clear out. None of these options work. Everytime we put wood in now, we open the door just enough to quickly put a split in, trying not to burn our arm, and then turn on the air purifier to get the smoke out of the room. GREAT SYSTEM!
I've added 3ft. of chimney pipe, so now its 3 ft taller than the old chimney, with no effect.

The only chimney differences between the new and old systems is the new system is 6" and the old was 8", which corresponds to the stove sizes. The 45's are lower on the new system but there is still 5ft of straight pipe before the 45

I'm at a loss

 

[moresnow]

Have you tried completely loading the cold stove?
Start your complete load with a fire starter such as a 1/4 puck of Super Cedar.
No need for kindling or small fire starts unless you have truly poor draft.
Get the entire load involved and up to temp and then incrementally reduce air supply setting for the long haul or required heat output.
Only open the loading door when there is virtually nothing left but minimum coals for a full load restart.
Adding a split or two occasionally like you would with an old school stove seems to be a real issue with the latest design.
If you get a chance, try this method and post what you find. Worth a shot perhaps.
Good luck.

 

[peakbagger]

The other assumption on draft calculations is how "tight" the house is. The standard assumption is that the house is neutral with the outdoors meaning no pressure differential between the indoors and the outdoors. That rarely happens, the house is normally negative to the outdoors and that difference needs to be made up by stack draft. It makes a difference on a marginal installations. The way to prove it is try the window test, open up a window to the outdoors before trying to reload, if there is less smoke its a good hint that the house is too negative, or the draft is inadequate.

On a modern home with an air to air heat exchanger there may be adjustments and tricks but in a typical home it can be battle as the tighter the home is made to reduce heating due to infiltration, the worse the draft gets. I have heard of several folks whose stove has smoke issues after they have had an energy audit and energy upgrade where outdoor air leaks are plugged.

 

[wetwood4life]

We have similar problems... been trying to track it down since the original install 3 years ago. We also keep an air purifier on standby if using the thing. Good luck to you.

One dumb question, only because I don't see it mentioned yet: are you bypassing the catalyst when you open the air? (side lever pulled forward, I believe). If not, you should be.

I've concluded when people suggest cracking the stove door before a reload, it's mainly so you don't suction a poof of smoke into your room by quickly opening the door. It's not for the draft problems you and I have, where the system would rather put smoke into the house than up the chimney.

 

[Prometeo]

I had the same problem in the second year > dirty flue

 

[garjess]

Letting the stove completely cool off before fully reloading would work, except for the fact the house will cool down while we're waiting.
This house isn't tight at all, so I doubt that is the problem. Even so, I installed a fresh air intake which should equalize inside/outside pressure.
The flue is cleaned every year. It also did this from the start when the flue was brand new.
I've looked at adding another three foot section but that will put the top about 8ft. above the ridge. I may try it to see if it helps but the last 3ft I added had no effect.

 

[garjess]

I finally fixed this POS stove design. I added 10ft of chimney to increase the draft with no improvement. Thank goodness a neighbor had some pipe I could borrow so I wasn't out any money. After trying other things, I added a piece of metal in the front to effectively lower the door opening. Now I can open the door without filling the room with smoke.
Why the stove was designed where the smoke goes out the front about the same level as the door opening I'll never know. The Lopi in my last house was exactly the same BUT had a bypass that blocked the secondary burn and opened a port in the back directly under the chimney. When the bypass was open the smoke went right up the chimney, if I forgot to open the bypass it was just like my new stove without the added piece.
The piece was simple to add. The stove has a piece there but it isn't low enough. I drilled three holes in the existing piece and bolted a longer piece to it. The stove isn't as pretty now, the door looks squatty and you can't see the secondary burn, but that's better than emphysema.

 

[neverstop]

I finally fixed this POS stove design. I added 10ft of chimney to increase the draft with no improvement. Thank goodness a neighbor had some pipe I could borrow so I wasn't out any money. After trying other things, I added a piece of metal in the front to effectively lower the door opening. Now I can open the door without filling the room with smoke.
Why the stove was designed where the smoke goes out the front about the same level as the door opening I'll never know. The Lopi in my last house was exactly the same BUT had a bypass that blocked the secondary burn and opened a port in the back directly under the chimney. When the bypass was open the smoke went right up the chimney, if I forgot to open the bypass it was just like my new stove without the added piece.
The piece was simple to add. The stove has a piece there but it isn't low enough. I drilled three holes in the existing piece and bolted a longer piece to it. The stove isn't as pretty now, the door looks squatty and you can't see the secondary burn, but that's better than emphysema.

View attachment 330650

I've thought about doing something like this to my shelburne. The smoke baffle (smoke shelf? whatever you want to call the plate that is supposed to be doing this..) is poorly designed.

Does the glass get dirtier now? Or is the airwash supplied from above where you bolted that plate in?

I feel like you could probably make it smaller and regain more of the fireview. My experience is that you get a lot of turbulence at the top and on the left side of the fire-box opening. You could probably cut the majority of that plate away leaving 0.75"-1" of material extending beyond the top/edges. You might be able to get away with cutting off more if you bend the material back into the firebox.

 

[GM80NY]

Does this one have a side door and a front door to load?

With my GM80 I dont think its made to be used where you add a few logs every so often. Its meant to be loaded up and ran for a long time. Or on the days where its cold night and morning and warm during the day only loaded fairly fully in the morning and at night.

Always if I open the door and there is unburnt wood we will have some smoke escape. But if there are only coals and I crack the door for a few and open the air all the way no stinky fumes escape.

Theres other factors like your wood moisture content. Hope this helps.