Smoke in house help

You're looking in the wrong place, I think. A leaking gasket will NOT normally cause a smoke smell in the house, as your stove is at a lower absolute pressure than the house, thanks to chimney draft. A leaking gasket will cause a stove to fire more strongly (see "overfire", "run away", etc.) than you desire, but should not cause any smoke leakage.

I suspect that what's happening is that you're getting a little bit of back-puffing, forcing smoke out thru the air inlets on occasion. You may not have observed this previously, if your stove was leaking. However, repairing the bad gasket(s) has enabled you to shut the stove more tightly, and this is one of the required ingredients for back-puffing. Try not shutting down the air control so tight (or so early in the burn), and see if that solves your smoke trouble.

Now, as to your last paragraph, that sort of plays into what I'm talking about... but I'm confused. Stove model is a Defiant "NC", as in "non-cat"? But you have a bypass damper?

I was going to suggest back puffing also. it happens sometimes with me when I'm in a hurry and don't really let the stove get burning and try and close it down too early.

Are you sure it's not coming from when you reload? The smell that is....

I've got a Resolute, so the same as you but a bit smaller and I run full time from fall to spring, except to clean out ash. You do need a lot of glue/cement to hold the gasket in place. The original one lasted me 20 yrs. but the replacements seem to be every 3 yrs now. Agree with others that it is unlikely the griddle gasket is leaking but I would not say 100% sure unless you used the wrong size. If it's oversize, the griddle will not go down all the way flush, if it's under, it could be a problem, esp if your wood is not fully dry, which I think is your real problem. The gasket should fit perfectly into the channel and once the griddle top is closed, the gasket will then compress to fit. The first replacement I got from a VC dealer was the wrong size, so don't rely on that.

To operate properly, the damper control handle on the left side should be up only until you get to 400+, then put it down all the way until it sort of locks for proper operation. If your wood is dry, you should easily get to 600+ with the damper arm in the down position. If it can't, it's because the wood is not dry enough. Done it for 30 yrs., guaranteed. I sometimes will put splits that are over 20% moisture and that's the only time i ever have a problem. And yes, you can get smoke because the wood is smoldering too much instead of burning properly. The air or temperature control on the back should be almost straight up with perfect wood and a bit right (or more open) with not so perfect - once the damper is down. The air control can be adjusted on the chain, so don't worry so much if it's not right.

My guess is that the weather conditions are now a bit warmer & damper, so you have a bit more problem with a good draft when you've got less than great wood.

Forgot to mention. If you are burning with the damper arm up, all your wood heat is going up the chimney. OUCH

gazelle said:

Forgive me; I am not as well versed as most of you on here so I may be using an improper term.

When I say close the bypass I mean I close the handle on the left of the stove when looking at it. This closes a damper at the top of the stove and forces the smoke/exhaust to travel down to the bottom of the stove a go through a ceramic re-burn system.

Because I seldom can get the stove to burn above 450 (when closed down), I keep the air control (lever on right if looking at the stove) all the way forward or open. So I do not think I am closing it down too fast. I keep it open to about 550-600 and then pull the left lever closed.

I do know what back puffing is because I have experienced it before. I do not think that is my case because I am not seeing the flash. I can detect a faint smoke smell from around the griddle. After a while that smell builds up in the house, more so in the rooms where the stove isn’t. It is not a function of my house being too tight considering I can see out of a few exterior door jambs from doors settling over the years.

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Okay, this is a standard downdraft catalytic stove, identical to my own two stoves, in theory. Ideally, you should be able to open the bypass, open the air control, load fresh wood, get it going good and strong, close the bypass damper, wait 5 minutes for the catalytic combuster to ignite, and then shut down the air control while maintaining cat ignition / clean burn. There are about a million things that can prevent this from working correctly, as you're observing. The downdraft cat is a great design, in terms of performance, but one of the most temperamental designs. VC compounded the problem by designing a stove that relies on many gaskets, refractory problems, and (on some models) too-complex air control systems.

So, we're just going to have to work thru what's causing you to be unable to burn this stove as designed, and in the course of that, we'll probably find your smoking gun (pun intended).

I'm going to ping jharkin, as he has a stove very similar to yours. He and I have been learning to burn these downdraft stoves together, over the last 3 years, and have learned a few things along the way.

First, can I ask where you're measuring your temperatures? Also, do you have a catalytic probe thermometer, or some other way to determine if your catalytic combuster is maintaining temperature / ignition?

I thought NC stood for non catalytic

"My stove is the white ceramic" I think you meant cast iron, not ceramic.

I hate to sound like a broken record but there is no way of knowing it your buddy's wood was under 20% moisture either. Even after burning wood for 3 decades, when I pull out my meter, I still get get surprised sometimes - in either direction. Even 20% is so-so for many and they want it less.

Okay. When he said "bypass damper" and "ceramic combustor", I thought he was talking about a cat stove. If this is indeed a non cat, I'll defer to others.

Joful said:

Okay. When he said "bypass damper" and "ceramic combustor", I thought he was talking about a cat stove. If this is indeed a non cat, I'll defer to others.

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Ya, VC always used to refer to the primary control as a bypass damper. That's what the dealer called it too. When I first came on this forum it caused me some real confusion with the terms.

To get back to the smoke, my door gasket is leaking for sure but when burning properly, you can actually hear air rushing in through the gasket, not out.

Have you cleaned your chimney lately ? What did it look like? Is the cap clogged with creosote? Poor draft could be part of your problem.

BTW, as I'm posting right now, my Resolute is gently back puffing and there is a definite odor of smoke that suddenly filled the air. I adjusted the air control and that stopped it. Sometimes you get a real burst and sometimes it is so gentle that you hardly hear or see anything. I hear the flap at the back clicking and know it's causing a problem. Wonder if that's what you are getting.

The VCs have been referred to as 'smokies' on this forum. It's something that I get used to, even after all of that experience. Probably my problem today is that I'm into next year's wood and although I measured it at 20% moisture, I'd be happier if it was lower. The wood in the stove at this moment was just brought inside this afternoon so the 20% moisture is still frozen and usually, I like to store a few day's worth in a warm place before loading it.

gazelle said:

to clairify things
I have a Vermont casting 1610 NC

The second burn is accomplished via the shoe refractory

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Good to clarify, but my original post is still correct. A leaky gasket on a properly functioning stove will not cause a smoke smell, as air is only drawn IN thru the leaky gasket, not out. You were good to focus on fixing the gaskets, as they're a safety / control issue, but not a smoke leakage issue. Smoke smell is almost always the result of wet wood, stalled draft, or back-puffing (... which is usually caused by wet wood or stalled draft).

Sounds like back-puffing. I am surprised you have not experienced this before though. It would signify a change in your system. My biggest guess is you are burning wetter wood than previous years (I am speculating as to this because of your low reported stove top temperatures). If the stove is smoldering and starved for fresh air the smoke will build up in the stove (increase in combustible fuel in the actual stove rather than the 2nd burn chamber in the ceramic refractory). Then when that fuel ignites, if there is enough fuel and pressure it will ever so barely lift that top loading plate up and a minute amount of smoke will escape with each "mini-explosion/combustion".

I have a video of my encore 2n1 back-puffing. You can see the flames go out for 10-20 seconds then a WOOSH of flames occurs (often you can hear an audible woosh too).

Now my stove rarely leaks smoke back into the house however. When I notice my stove doing this, I open the air just a tad until I see a small gently flame constantly (sometimes just in the back...). The only time the back-puffing has been strong enough to leak smoke back up through the top loading plate were with very high winds outside.

This is MY best guess as to what is going on.




You other issue would be your stove top not getting over 400-450, as previously posted implying wetter wood. It doesn't catch as well, it is using heat to convert the moisture to steam which keeps the temperature down, the heat production down, and in conjunction leads to poorer draft and smoldering wood which then leads to excessive accumulation of combustible smoke in the fire box instead of in the combustion chamber.

Again what I suspect based on what I know about these stoves and how mine acts and others who have posted here act. Others will pipe with much more knowledge than I.

gazelle said:

So I do not think I am closing it down too fast. I keep it open to about 550-600 and then pull the left lever closed.

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Do you go from all the way open to all the way closed as far as the air lever is concerned (not the left damper bypass, but the right air control)?

If you are going full open to full close this will frequently cause backpuffing. I can make my stove back-puff if I close this level to quickly and all the way. More frequently I am running with this lever about 50-75% closed, but I think there may have been some change to the way the air control works as when I get under the stove and move the lever I can see the intake almost fully closed at 75% or just passed it. I am pretty sure I have to adjust the secondary air lever mechanism this summer because I know for a fact when I first got the stove 2 years ago it was 100% closed at 100% not just past 75%.

The air control is meant to be back down in increments either 25% or 33% at a time over 5-15 minutes rather than full open to full closed. Not sure if this is the case in your situation though..

Sorry last post. I am actually confused after reading your quote I quoted again and this would affect the point I was trying to get at above:

"Because I seldom can get the stove to burn above 450 (when closed down), I keep the air control (lever on right if looking at the stove) all the way forward or open. So I do not think I am closing it down too fast. I keep it open to about 550-600 and then pull the left lever closed."

The right lever is open during reloading (appropriate). You close the left lever (damper bypass) and you still keep the right lever open all the time? Or do you close this right lever after closing the damper bypass as well?

If you have to leave the right lever open all the time it does suggest a few possibilites. 1) wet wood again 2) possible problems with the 2nd air mechansim.

Make sure by getting up under the stove and looking towards the rear underside where the combustion chamber that the rectangular air control is properly opening and closing with the right air lever.

ok time for me to stop muddying the waters!

Hi all... Joful asked me to stop in and take a look... Ive been away ....


Yes, the OP's stove is a non-catalytic. The Vermont non-cat system still uses a bypass as it works something like the Harman firedome system in that there are no burn tubes and rather they have a ceramic reburn chamber in the rear of the stove where smoke is mixed with pre-heated air. This chamber is made out of the same fibrous ceramic refractory material that is used for the catalyst chamber on a vermont catalytic, AND its located in the same place as a cat chamber would be so they do get confused at times.


Vermont stoves have two controls, seen from in front facing the stove:

• The bypass handle is on the left, and the Vermont Castings user manuals call it a damper. I like to say "bypass damper" to avoid confusion. pushed to the rear send the smoke straight out, pulled forward directs the smoke down through the return chamber.

• The primary air intake control lever on the right. Vermont Castings user manuals call this a thermostat lever, as it drives the air intake via a bimetallic thermostat. pulled forward is wide open, pushed to the rear is closed.

I'm not an expert on the operation of the NC but its supposedly somewhat similar to the cat. Burn with damper open till its reallly hot (500+ griddle for cat, maybe you want to aim higher like 600), then close the damper and slowly start dropping the air control down in stages. the noncat system is particularly difficult to achieve light off and Ive heard it said that when its working you should hear a roar in the back of the stove. If you dont get the griddle hot enough before closing the damper and/or you shut the air control to fast you can stall the reburn system. In that case smoke backs up in the firebox and then periodically you'll get a burst of flame and the classic back puff.

Any stove can push smoke into the room from a back puff, but VC stoves are particularly bad about this if that griddle gasket is not perfect. In fact if you get a really powerful back puff you might even see that griddle jump and burp smoke!

Thinks to check:

1- Good dry wood! If you are unsure of your supply buy a couple bundles of kiln dried at a gas station, or mix in a couple cut up 2x4s and see if it improves

2 - Make sure your chimney draft is as good as it can be. Clean your flue and if you have a restrictive top cap, key damper or other obstruction in the stack get rid of it.

3 - Check all your gaskets again. Everything should pass the dollar bill test. Be especially suspicious of the ash pan gasket. For the griddle, if you dont get a good seal rip out the wirewound gasket and use plain 5/16 braided rope gasket (this is what I do, it seals better).

4 - Try a burn cycle like this:
- start your first small load and let it burn down to establish a good 2in base of coals
- add a new load and with both damper and air control wide open burn till the griddle hits 550-600
- close damper and leave air wide open
- close air control slowly - say 1/8 of a turn at a time every 5 minutes aiming to keep the griddle temp over 500. While you do this watch the chimney outside, if you start to see dark smoke open it up some more, if the exhaust is clean you can keep closing it down.

We had a VC Resolute Acclaim for 8-9 years, down draft non-cat. Had same problem after 3 years of good service. The bypass damper gasket was the main problem. If that gasket doesn't seal 100% it will back puff and act up. Real PITA !

This stove also needs VERY DRY wood. If more than 15% or so moisture in the wood, the box fills with smoke and will leak a little out.

Got to have a deep bed of coals on the grate to work right, enough to completely cover the lower draft exit.

You also might need to replace the soft fragile secondary burn refractory. I was going to do that, but decided to replace the stove... The day I got that thing out of the house and put in a Jotul was a great day here!