Carbon Monoxide from Lopi Insert

[Steve173]

Hey yall!

I have a Lopi as well and I'm getting CO in my house as well, no smoke, draft is great, wood is really good too, dry and seasoned. I'm scratching my head to what it could be. Its always at the end of a burn when the coals still giving off some heat, but not a mature fire. I do not have gas heat or gas appliances. Had the fire department here 3-4 times to confirm the CO levels in the house while the alarms were going off. The alarms have gone off many more times than the fire department has been here. It's a real head scratcher. The shop that sold it to us has been out to see what could be done and they did some fine tuning but it still did it. The weird thing is the 1st year no problems at all the last year was a train wreck. Had it professionally installed. Also installed a different cap.

My theory is around the bypass if you look deep into the stove you can see flames which is pretty normal, but after the fire reduces to coals, and the fan is still on, I'm wondering if the ports where the hot air is blown out of is sucking the CO out. The 2 spots flank the bypass rod and maybe, just maybe the chimney isn't hot enough to pull the CO up and out maybe the fans that are flanking the bypass rod are creating a "vortex" and pulling it in the house? I feel like I'm guessing now because I don't know what else to do

The shop that sold us the unit doesn't know what else to try either. They gave us about 4 options of other brands but my wife will like one but I'm focused on performance and she's concerned about the aesthics not sure what else to try. The ones he's recommending is units that don't have a bypass.

Any ideas?

Thanks

 

[begreen]

It could be draft reversal. Describe the flue setup and stove location. Is this a basement install? Is the flue connected to an exterior chimney?

Have there been any other changes in the house last year? Kitchen remodel? New exhaust fan?

 

[Steve173]

It could be draft reversal. Describe the flue setup and stove location. Is this a basement install? Is the flue connected to an exterior chimney?

Have there been any other changes in the house last year? Kitchen remodel? New exhaust fan?

6" liner up a single story chimney, no remodels, we don't have a basement, the flue does go up an exterior chimney all was professionally installed, and no new exhaust fans. It usually only does it towards the end of a burn. I'm stumped. Any help would be awesome! 🤠

 

[begreen]

There may be negative pressure in the house or inadequate draft. How much vertical height in the flue system? Are there any long horizontal runs?

The details of the flue are important. Was it connected to a clay chimney liner or was a new, 6" stainless liner installed? If a liner was installed, was it insulated? Include pictures if possible of the stove and flue connection inside and the chimney outside.

 

[Steve173]

the liner was a new stainless steel liner, it was not insulated. at the connection point where the liner meets the stove it was sealed with some high heat sealant/caulk designed and recommened by Lopi in the owners manual. the chimney is a masonary brick fireplace that is on an outside wall I uploaded a picture the chimney from the street. its pixelated a bit and a tad wonky but I think it'll give you a bit of an idea. I thought I had a picture the insert on my phone but unfortunately I do not. by you asking these questions, I am starting to wonder if insulating around the liner would keep it warmer longer towards the end of the burn so that the CO would still go up the chimney vs inside the house since the liner would stay warmer longer? I'll snap some pictures when I get home the cap I have on now is a better one this is an older google picture.

 

[begreen]

Yes, the liner should be insulated. That will help draft. What I am trying to determine if there is enough height for the stove. Typically these inserts want at least 16' vertical. The picture helps. Looks like maybe 14-15'?

I'm assuming that this is not up in the mountains at high altitude. Is that correct?

 

[Steve173]

correct, not in the mountains, I am about 380ft above sea level on the west coast in WA state

it may be a bit more than 15 feet of vertical. I'll double check that, but it should be pretty close to the minimum 16' vertical

sure appreciate your help with this!!

 

[begreen]

If the flue is too short, that can be tested and remedied. Another possible problem could be house related. If the house is not well sealed above, and there is are leaks to the attic (leaky door, ceiling registers, ) or a window above that is open, the house can act like a chimney, lowering the pressure in the living room.

 

[Steve173]

To the top of the cap is about 15' maybe 16. How do you test if the flue is too short?

The majority of the home is a single story the only stairs are about 5 steps up to the master bdrm and about the same down to the rec room both these rooms are on the other end of the house. I'm not sure where to begin if it's the house.

Thanks!

 

[EatenByLimestone]

How warm is it outside when you’re seeing the draft issues?

 

[begreen]

A manometer or magnehelic is used to measure draft strength. By the description, this may be the issue. It is common in places where the fireplace is in a one story section of the house that has two stories. Especially when the short side of the house faces the prevailing winds.

A non-commercial service in support of responsible home heating with wood - How Wind Affects Chimney Performance

The Wood Heat Organization was formed to support the public in the responsible use of wood energy in the home. We fulfill our mandate by providing reliable information, by conducting research into wood heating-related issues and by representing the public interest in discussions of policies that...

www.woodheat.org

 

[Steve173]

How warm is it outside when you’re seeing the draft issues?

That's the weird thing, no draft issues. CO doesn't come in the house at start up or during the burn it's pretty much towards the end of the fire. Plus rhe first season we had it it worked like a champ. I'm in the Seattle tacoma area so it doesn't get crazy cold here. It might get into the teens for a little bit but it's usually just warm enough not to snow, but we can get it for sure

 

[EatenByLimestone]

It only happens at the end of burns. I suspect, because it may be a different cause in each situation, that these are all draft issues. The only time I had it happen to me was on a chimney that had marginal draft and a fire that had died to coals.

Carbon monoxide happens when there is incomplete combustion. There isn’t enough oxygen to feed the fire.

When you start the fire, the entire firebox is full of fresh air. There’s plenty of oxygen in that air. As the flue warms up, it pulls enough fresh air through the very small air intake holes on the stove. The fire is happy and all is good. As the fire draws down and is reduced to coals, the flue cools so it isn’t pulling fresh air in as hard. You get incomplete combustion and carbon monoxide as a result. Not enough fresh air is being sucked into the very small intake holes on the stove. Since there isn’t air being pulled into the holes, the carbon monoxide is free to leak out.

 

[Steve173]

One option that I am being offered is to switch out this insert with one that does not have the bypass option. the owner of the company that sold us the unit has been out to investigate but we're all really baffled. He's really trying to help. I have another property in the area with a wood insert(Regency CI2700) and there are no issues there. In fact this place is down in the valley and can be prone to downward atmospheric pressure since that place is close to sea level, but no issues there at all. they are willing to switch out to either a Cascade by Kuma, or Matrix by Osburn. I'm more about performance, but my wife is about the aesthetics side of things so its been hard for us to agree and I feel like we're settling plus who knows if it'll happen with the next one.

 

[stoveliker]

Given that the cause is in the capability of the flue system to draw in enough air into the stove and (exhaust) up out the chimney, I do not think a different stove will make a significant difference.
It is true other stoves may breathe easy (need less draft - suction - to operate), but all stoves need a minimum draft to avoid exhaust (w/ CO) to escape into the room.

The point as explained above is that the temperature of the flue creates the draft. Evidently, the temperature of the flue drops sooner than should be at the end of a burn, creating insufficient draft (suction on the stove) resulting in CO in the room.
The main thing to do is to either increase the flue (taller flues create stronger suction at the same temperature), or insulate the flue to slow the cooling down.
If they can pull the liner up and wrap insulation around it, that'd be ideal imo.
Adding a section on top of the chimney is possible but may look ugly if it's just class A (and would be expensive if you extend the brickwork to make it look better). I'm not sure how much insulating the liner would be to compare.

 

[Steve173]

it was just bizarre that the first season we had it the thing worked great, in our second season it has been a train wreck. had the liner and unit cleaned but it wasnt horrible dirty either. it doesnt get crazy cold here, it definitely gets chilly, which is probably why they didnt mention having it insulated and extending the liner/chimney or adding a chimney extender.

 

[stoveliker]

When the liner was cleaned,.did they clean the cap?

I don't know the insert, but is there a baffle that could have (sweeping) debris on top, blocking some flow?

Weather, home (air sealing?), and surroundings can be different from year to year leading a marginal install to perform one year and not the other year.

 

[EatenByLimestone]

The operator has more experience and might be fine tuning the burn, causing an issue when down to coals too. You may have been keeping the air open more in year 1, which may have let more air up the flue.

 

[Steve173]

When the liner was cleaned,.did they clean the cap?

I don't know the insert, but is there a baffle that could have (sweeping) debris on top, blocking some flow?

Weather, home (air sealing?), and surroundings can be different from year to year leading a marginal install to perform one year and not the other year.

Yes the cap was cleaned as well, he also had some little brushes to clean inside the firebox as well. He was pretty thorough

 

[Steve173]

The operator has more experience and might be fine tuning the burn, causing an issue when down to coals too. You may have been keeping the air open more in year 1, which may have let more air up the flue.

that is a possiblity, but I think I should be able to dial it way down and still not have the CO in the house.

 

[Steve173]

I gotta tell ya, I sure appreciate you all trying to help me figure this out. I've been going bonkers trying to figure this out