Help!😩Smoke Billows in Room! NEW Majestic Biltmore 42”

[No More Smoke-Shows:(]

Help, please! We have a new home with a detached (don't laugh) "She Shed," all completed in late 2022. The Shed has a wood-burning fireplace that billows smoke into the room within seconds after closing the window (as long as you leave it open, it's okay). I've attached photos of the actual fireplace, the exterior of the Shed, and the "floor plan/blueprint" of the Shed.

Here are some details about the "She Shed" and fireplace:

-Majestic Biltmore 42" (Model SB-80)
-The standard front opening dimensions are 28.5 tall x 42" wide (the height's now slightly reduced after we added a smoke shield, which didn't help.)
-The Shed has an ERV (no furnace - the Shed's heated with hydronic in-floor heat.)
-The square footage of the Shed is 434, with fewer bathrooms, so the two rooms (living & bar area) total around 390 sq. Ft.
-The chimney has a slight offset, and the chimney (started shorter) but has been extended to almost 19 feet tall (from the FLOOR of the Shed).
-The smoke billows in the same regardless if it's a cold winter night or a hot summer night.

We've had an HVAC company out where we've tried adding a fan to the exterior of the ERV intake to give the fresh air intake a "booster." We then tried adding that fan to the "Chimney Air Kit" & the "Outside Combustion Air Vent." We tried this with it blowing air into both at the same time and also into each vent separately. The only one that made a "slight" difference was when it was only blowing through the outside combustion air intake (which is the intake that leads to the cavity around the lower part of the fireplace). However, it still smoked within seconds of closing the window. Before these tests, the HVAC guys tested the air pressure with some device (he said he wasn't a fancy one). First, he said it seemed balanced; then, he said it was slightly negative. However, he said that adding the fan to boost the outside air coming in should've made it positive (but who knows).

Now, I'm not very familiar with fireplaces. Still, one thing I found odd was that even though this fan was blowing quite a bit of air through that Outside Combustion Air Intake, I couldn't feel any air around the fireplace openings. I'm unsure where that air goes and how it aids with the fire if you can't even feel it.

The company that installed it and everyone else trying to help are all scratching their heads. I'd be okay with leaving the window open, except that in our nasty winters, the window is right in the seating area. Hence, we need to wear a parka in this space because of the cold drafts that the open window brings with it. Not fun.

Any help would be GREATLY appreciated! Thanks kindly in advance.

 

[Ctwoodtick]

Is the company that installed it trying to work with you and trying to fix things? It really is on them to get this sorted for you. I’m sure some folks here will give you some thoughts on what may be wrong, but the company that did the install has a responsibility to have the thing be functional without a window open.

 

[No More Smoke-Shows:(]

Good evening! The company who installed it has been trying to sort it out; however, at one point they said they’d try what they can, but that they might be unable to resolve it. My fear (and the reason I thought I would try this forum), is that everyone here seems to be on the last of their ideas. Then we‘ll be stuck with a smoking fireplace.

 

[begreen]

That fact that the fireplace works correctly when a window is cracked open indicates insufficient combustion air. This could be due to an improperly installed outside air connection to the fireplace. Has it been checked for blockage. Something like a kink in the flex air duct could do this. Or that the ERV is not sized right, or improperly setup, or malfunctioning.

It would be good to go through these systems, one by one, to verify there are no hidden issues or bad assumptions.

 

[kborndale]

If the installers told me they can't fix my smoking fireplace and I am stuck with it then the next place I would be seeing them would be at small claims court.

 

[blades]

the only possibility, not mentioned by the op or anyone else is a reversed flue draft when first starting up. it was not stated the type of flue, insulated or not. depending on the surrounding buildings, vegetation , and topography you could be dealing with a negative area at the flue exit. There are a couple of companies that make draft fans for the top of the flue, and this sounds like what you need to resolve the issues, after first making sure the combustion air supply line ( outside air intake ) is free flowing.
It is also possible that something in that prefab fire place is not correct, maybe the damper control is not working properly- not fully opening the damper. Fireplaces need a lot of air, in one of my former homes I had a beautiful fireplace and surround. it also was a gas fired or solid fuel unit. There were cold start issues with it but once past that it would suck heat right out of the house to point of causing the gas furnace to run. It had a 12" id flue, all of 12 ft long. There was no provision for a out side air supply. 1950'S build. it was quite large. Put an insert in it, ran the 6" flue from that up the the 12" ( with a block off plate of course) and added the outside air supply system . built and installed a set of bifold doors for the entrance to that room. Wasn't perfect but at least it wasn't sucking all the heat from the rest of home out.

 

[bigealta]

Begreen's blocked or kinked intake vent line suggestion seems very possible. If it was me i would have put in a woodstove instead of a fireplace. Fireplaces take way to much air out of your house without adding much if any heat.

 

[webby3650]

The outside air kit is a 4” pipe. Your flue is 11”, I don’t see it providing enough air to be of much benefit.
To those saying they’d sue the installer: this is a fireplace system. If it is installed correctly, and they have taken extra steps like adding chimney beyond the required amount, how can it be their fault? It tells me there is something wrong with your house. These are factory built and will work unless something in your environment prevents it from working.
Also, it’s still pretty warm out for a fire, they perform much better once it’s cold enough to want or need a fire.

 

[kborndale]

The outside air kit is a 4” pipe. Your flue is 11”, I don’t see it providing enough air to be of much benefit.
To those saying they’d sue the installer: this is a fireplace system. If it is installed correctly, and they have taken extra steps like adding chimney beyond the required amount, how can it be their fault? It tells me there is something wrong with your house. These are factory built and will work unless something in your environment prevents it from working.
Also, it’s still pretty warm out for a fire, they perform much better once it’s cold enough to want or need a fire.

So your saying that if I hire a professional to install a fireplace and they can't get it to work that I have no recourse? That's ridiculous. I paid them for a functional fireplace and if they can't make it functional they need to refund me.

 

[bigealta]

The outside air kit is a 4” pipe. Your flue is 11”, I don’t see it providing enough air to be of much benefit.

So maybe 1 or 2 more OAKs needed? Hmm not sure that's gonna fit.

 

[webby3650]

So your saying that if I hire a professional to install a fireplace and they can't get it to work that I have no recourse? That's ridiculous. I paid them for a functional fireplace and if they can't make it functional they need to refund me.

It is functional is what I’m saying. Something in your house is preventing it from working properly. Assuming it’s installed properly. This sounds like a situation that’s out of their control is all I’m saying. When a fireplace is installed in new construction there’s now way to know if other things will be done to the home that will make the air unbalanced and prevent the fireplace from drawing properly.

 

[webby3650]

So maybe 1 or 2 more OAKs needed? Hmm not sure that's gonna fit.

Some larger units have 2, this only allows 1. I don’t see how it’s enough, but it’s most common.

 

[bigealta]

Ok so:
Make sure All blowers are off:
All vents off
Kitchen fans, bathroom fans, dryer, furnace, gas hot water heater, anything that blows air from inside the house to the outside.

Then try again to light your fire. Also a top down start could help. And of course dry seasoned wood for hotter fires with less smoke.

See how much of a difference these can make, and find out where the draft robbing culprits are.

 

[webby3650]

Ok so:
Make sure All blowers are off:
All vents off
Kitchen fans, bathroom fans, dryer, furnace, gas hot water heater, anything that blows air from inside the house to the outside.

Then try again to light your fire. Also a top down start could help. And of course dry seasoned wood for hotter fires with less smoke.

See how much of a difference these can make, and find out where the draft robbing culprits are.

Also, wait until it’s cool outside. Chimneys don’t draft, or draft well when it’s warmer outside than inside the home. This will play a major role here.

 

[Prometeo]

need OAK in new house

 

[kborndale]

It is functional is what I’m saying. Something in your house is preventing it from working properly. Assuming it’s installed properly. This sounds like a situation that’s out of their control is all I’m saying. When a fireplace is installed in new construction there’s now way to know if other things will be done to the home that will make the air unbalanced and prevent the fireplace from drawing properly.

It's not functional. It's smoking the room out. I paid for a functional fireplace. If I don't get one then I'm not paying for it. I wouldn't have paid the final 50% until I had a functional fireplace and if they couldn't make it functional I would have been taking steps to get the rest of my money back.

 

[kborndale]

need OAK in new house

Has oak in house.

 

[Prometeo]

Has oak in house.

it is very strange if "oak" is correctly connected to the fireplace, there should be no difference between closed and open window, this assumes "oak" is not connected well to the fireplace, I don't know if this is a hot air duct. Have the installers got the wrong outlet?

 

[begreen]

There are two air intakes required for installation in Canada. Chimney air and combustion air. Were both installed?

A P trap in the outside air supply is recommended for this unit in cold climates. That is what has me wondering if it got a kink in it. A test should be performed to verify that there are no restrictions in the combustion air supply.

 

[Prometeo]

Indeed, that's not an oak but a chimney draft reducer, which is completely useless being less than 18 feet tall, you need combustion air that communicates with the outside to solve

Majestic CAK4A Chimney Air Kit for SL300, 8-Inch Inner, 10.5-Inch Outer

Premium Design - Quality construction for long-term durability Efficient - Reduces negative pressure within a chimney

www.fireplacesdirect.com

 

[No More Smoke-Shows:(]

Thank you everyone for your suggestions. To answer your questions:

-Yes, we have both an “Outside Combustion Air Vent” as well as a “Chimney Air Kit” installed (see photos which show these at rough-in stage, before the walls were boarded over).

-As for the outside air temperature, this fireplace did the same thing all winter (it was actually in winter we used it for the first time and discovered the problem, and we have very cold winters here in Canada).

-The fireplace doesn’t just smoke when starting up the fire. You could have a roaring fire going for well over an hour, and within seconds of closing a window it will billow into the room (So I’m not sure if a top down starts would help?). I tried attaching a video of the smoke, but can’t seem to figure out how to attach it.

-I did ask about adding a fan to the top of the chimney to help with the draw, and was told that it would be against code in our area.

-A different fireplace company in town sent me this link to a vent that they suggested we install in the room (it just goes from the exterior into the room, not directly to the fireplace). https://www.condar.com/ASV.html I’m not sure if it might help? I thought I should try to test it by mimicking it before installing one. I thought perhaps I could cut a big piece of cardboard the same size as our window screen, and cut a small circle out of it (the size of this vent). Then put that over the window screen to see if this small “vent/hole” would bring in enough air to work?

-As some of you suggested, I am now curious to know if there is a blockage in the Outside Combustion Air Vent. In the first message I posted, I mentioned that we tried putting a fan on the outside of both this vent as well as the Chimney Air Vent. The only one that “slightly” made a difference (but still smoked) was when we added the fan to this Outside Combustion Air Vent. Now, I know very little about fireplaces, but I was surprised that I couldn’t “feel” any air coming in, even though there was a fan pushing air through. Excuse my lack of fireplace knowledge, but how is this air supposed to make its way to the fire? There’s the “brick surround” which It can’t get through; so is it supposed to come through that 1 inch gap (space) that is just behind the marble face of the fireplace surround? If so, I can’t feel any noticeable air there.

My questions: How would I go about checking for a blockage in this Outside Air Vent? Also, it was mentioned to confirm the “open & closed” mechanism (lever) to this vent is operating properly. When I move the lever I can hear it moving, but not sure how to know if it is operating as it should?

Any other suggestions or questions would be appreciated. We are all truly stumped around here.

 

[Prometeo]

your chimney flue is too short to even have a draft damper, the draft reverses direction! remove the stud you have outside If I'm not mistaken you have two tubes inside, close the draft reducer tube momentarily and test

 

[begreen]

Thanks for the follow up and detailed pictures. The ducting looks proper. Based on what has been described, there is negative pressure in the room. This can be made worse at times if there is an exhaust fan running. Large kitchen hoods are a common culprit, but bath fans and clothes dryers are also exhausting air. A radon gas exhaust system is another suspect.

If the problem exists even when all the above fans are off then something is causing a chimney effect in the house. Culprits can be unsealed attic vents or doors, open second story windows, etc. This chimney effect is more common in one-story additions to a two story house.

Another issue can be if the prevailing winds are pressurizing the area above the chimney.

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...

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If all the above are eliminated then it sounds like the ERV is not sized right, or improperly setup, or malfunctioning.

 

[bigealta]

"Another issue can be if the prevailing winds are pressurizing the area above the chimney."

This can be a big problem with a short chimney like in begreen's diagram.
It happens to my woodstove in Utah on even a full hot burn when the wind is out of the north west. Smoke puffs out the air inlet vent dial and out the stove door too if opened.

So no fires when NW winds are in the forecast. Thankfully it's not very often.

 

[gthomas785]

Isn't the combustion air vent supposed to be below the level of the firebox?