Combustion Air

[Rotro]

We have a insert that was installed recently with the blower ventilation for warming the room air (I call ventilation or recirc). Prior to use, we found the wind from outside blows through those vents into the room.

I read the manufacturer's literature and it states the damper is not positive shutoff, and that the combustion air can either be ducted to the outside, or to the inside room between the surround panels or ducting at the bottom of the chase.

The installers did none of that and just left the combustion air intake open to the chase. So the air is going down the chimney pipe, out the combustion air inlet, and into the ventilation top and bottom, then into the room.

Without going into the communications with the installers, is there any violation of code? The only thing I found in NFPA is to follow the manufacture's installation procedures.

We can not have wind blowing into our house all year long and I don't want to put painter's tape over the vents when not in use.

 

[begreen]

Welcome. What is the make and model? This sounds like a Zero Clearance fireplace, but maybe not? Pictures are welcome.

 

[Rotro]

Pacific Energy, FP30 Arched LE with the Craftsman Surround. You're right, zero clearance.

 

[begreen]

Thanks. Marketing sometimes calls these units inserts, but that is misleading. It's a good, ZC fireplace. Outside air connection is optional on this unit. Are there any pictures of the install before it was sealed up? What type of chimney pipe was installed?

 

[Rotro]

I don't have photos of the combustion air intake area of the chase before sealed up but the installers acknowledge they did nothing except take to cover off of the right side ( as looking at the photo above). We love the stove if there was some way to stop the air blowing into the house without making it look terrible with something like the magnetic coverings I read about. Surely the manufacturer didn't intend for that. Reading the manual, it appears to me they didn't. This wouldn't be the first thing we've had to deal with on this install so I expect it's probably wrong. I can't make them fix it unless I can prove it.

The chimney pipe I believe is triple wall stuff. That all seemed good to me.

 

[Rotro]

And as far as that goes, having the recirc fans suction right at the combustion air intake, as it is now, doesn't seem safe to me.

 

[begreen]

Is there a ducted remote hot air kit installed? If not, the recirc fan is supposed to be intaking room air, not chase air. Is there a slot or grille directly under the door for the convection air intake?

 

[Rotro]

I guess I should say no. The recirc fans are taking room air below the door. But it's all open in the chase. It appeared to me that's how the unit came. I assumed by photos, the vent fan ventilation came into the chase and blew out of the chase. This is my problem, the combustion air also comes from the chase as installed. So back drafts when not using the fireplace blows out the vents. And there's no way to stop it with the 20% damper thing.

Are you saying there suppose to be some ducting stuff between the room air inlet and the fans? That would solve my problems! Hopefully I'm reading that right. Except there still needs to be combustion air from somewhere... hmm...

 

[begreen]

Without seeing what is actually in place (or not) in the chase, I'm just speculating. The fireplace comes with a convection fan that pulls air in under the ashlip and blows it out above the door via the convection jacket around the firebox. This is a closed system that should not be open to the chase. The remote blower system is separate and optional.

 

[Rotro]

I may have a misunderstanding. When the unit arrived on the truck, the bottom was open and I could see the vent fans. I assumed they made the platform and placed in on that platform just like that. Looked through all my photos I took when I complained about my siding and J-channel just dangling in the chase, but I didn't take one of the unit sitting there. So, they very well may have put side covers on, or didn't and I misunderstand how the fans work. I am pretty sure the power cable is just strung directly over to the fan's terminal strip... but I can't say that with 100% confidence now.

The combustion air intake though, is just an open hole. The installer states this is the way you do it and that the manual's description of how it's suppose to be ran is a copy/paste error from another unit. It supposed to be chase air. I don't believe him. Now, a back draft blows out that hole and primarily out the bottom grill front but also on the top. How it's getting there I guess I am not as sure as I was yesterday. When it was really cold and windy, my wife and I put an electronic thermometer on the wind coming out the vent grills, without the fans on, and it was 40 degrees or less. When I complained the installer said I needed to build a fire.

What if I don't want to build a freaking fire? We have wind blowing into the house through the vents?

So we did build a fire, the blowers finally kicked on, and the air coming into the room slowly crept up. We've had a fire non-stop ever since, until I can figure out what the freaking h.e. double hockey sticks is going on. Occasionally in the morning the fire will just be embers and the fans are blowing cool air into the house which also made me believe the blowers are getting air from the chase.

I've tried at least six times over a couple weeks to get the manufacturer to either call me, email me, or even send me a letter if they want to on their webpage but they wont. They will not respond to my request for technical assistance... that's why I am here. I think my installer is a liar and I can't get the manufacture to respond.

Maybe everyone has wind blowing out their vents on the FP30... if so, I am replacing this damn thing already. I guess I need to see if a different company will come look at this. Thank you.

 

[Rotro]

According to the installer, below is from the manufacturer to them, which reads like air coming out the vents is by design. I'm curious how the manufacturer can provide an installation manual that apparently is wrong, when their UL listing references NFPA which says to follow manufacturer installation directions. No where does it state that combustion air comes from the room air recirc intake. So, I guess it isn't a closed system after all and tied together. This isn't going to work...

"
Yes, we can pull air from the room... it will come into the unit through the bottom louvers.

See item #2 below ---“between the surround panels” is cut and pasted from another wood burning unit document that has a surround panel... in this exact model it pulls air in via the bottom louvers

NOTE: we have to always remind ourselves so we can explain to the homeowner that air will always follow the path of least resistance... so hopefully we do NOT have negative pressure in the home (no kitchen vents running , no bathroom vents running, no clothes dryer running or anything else that is going to pull air away from the fireplace)... in real life we do have those vents running so in real life with those vents running and no fire burning.. our chimney and wood stove becomes a fresh air inlet to the home to relieve the negative pressure caused by those items running.
"

 

[GG Woody]

How is there wind in your chimney chase?
Is there not a chimney cap?
is the old fireplace cleanout being used as the combustion air? (this is fairly common)

 

[GG Woody]

I found a bunch of info here: https://www.pacificenergy.net/wp-content/uploads/2024/02/100004186-FP30_FP30AR-LE-071124-52.pdf

It includes this, which at a minimum is what I would do:

Installation:Outside air may be drawn through either side or back of the unit by connecting 4"(102mm) rigid or flex pipe onto the outside air adapter opening provided on the either side of the combustion air box. The fireplace comes with the outside air adapter factory installed on the right side. You are able to switch this with the cover plate on the left side if required. We recomend insulated flex when being installed in cold climates.

 

[Rotro]

The manual says three ways to get combustion air : either outside, from the spacing between the surround, or ducting at the bottom of the chase. According to the installer's claimed manufacturer's response, this is copy/paste error from another unit and the combustion air comes from the same place as the recirc air intake open to the chase - so this is where the back-draft is going into the ventilation. The installers just removed the cover for combustion air and that's it. They didn't run it anywhere. Per the installer - which after re-reading the blowers are in fact open to the chase:

"I spoke with the manufacturer, and they said it is not a common issue, but it does happen. The unit uses the air from the chase to feed the fire, so the plate is removed to allow this. That is how the unit has to be to function. They said cold air falls and the warmth in the house is sucking that cool air through the vents. The blowers are located at the bottom, and it is not completely sealed so that is the air you are feeling."

 

[Rotro]

If I can get to the bottom area of the insert, I wonder if I can run that 4" flex pipe out to the side of the chimney. I have a brick saw and might be able to attach something pretty for outside air source on the combustion side. The only air leakage then would be from the chase. And yes, we have a chimney cap. This seems like a terrible design but my familiarity with inserts is only this one. I looked this morning for another company to come check it out but the first one only services their own stuff and the others are chimney sweeps and junk. I doubt a home inspection company hires anyone that would know anything related to this.

 

[GG Woody]

I don't see a problem getting combustion air from the "chase" if there is combustion air available in the "chase".
I wouldn't want my blowers exposed to the "chase".
I would want my combustion air ducted out of the blower box, (as shown in manual) and the blower box sealed to inside air only, not "chase" air.
I do ducting for a living.
How is wind getting into your chimney "chase"

 

[GG Woody]

In my house, for my P.E. insert I have brought a combustion (fresh) air into the existing (1970's) fireplace cleanout, it gives fresh air underneath the fireplace (chase) that it can use if the house is under negative pressure.
The fireplace fan is a separate "duct" or "plenum" built within the fireplace.

By looking at your manual I can see that with a short piece of 4" flex pipe you can have your combustion air intake ducted out of your fan "plenum" to a factory knock out, and not have drafts associated with your fan plenum. Now your "chase" would need to have combustion air available to it.

 

[Rotro]

The chase is as sealed as the chimney cap can provide. No openings on the chimney. Apparently the air is going down the chimney pipe, out the combustion air inlet, and into the vent system. And since I can only shut the damper control to 20%, there is no way to stop it.

 

[Rotro]

In my house, for my P.E. insert I have brought a combustion (fresh) air into the existing (1970's) fireplace cleanout, it gives fresh air underneath the fireplace (chase) that it can use if the house is under negative pressure.
The fireplace fan is a separate "duct" or "plenum" built within the fireplace.

By looking at your manual I can see that with a short piece of 4" flex pipe you can have your combustion air intake ducted out of your fan "plenum" to a factory knock out, and not have drafts associated with your fan plenum. Now your "chase" would need to have combustion air available to it.

That's a good idea if the fan plenum wasn't open to the chase too. As of right now, I've convinced I have to get into the bottom of the insert, where the fans are, and do some modifications.

Edit: Your response just gave me more ideas. I can probably seal up the fan plenum and run the combustion air to the chase like you said, and make an opening on the outside of the chimney for air in. Is that what you're thinking?

 

[GG Woody]

From what I can tell, it has nothing to do with your damper control. It looks like your chimney is directly open to the box under your fireplace and that box is directly open to your room. Your damper control will be built into the combustion air circuit inside your fireplace.

 

[Rotro]

But if the air is coming backwards, wouldn't it go down the chimney pipe, into the firebox, through the damper controls, and out the combustion air intake?

 

[GG Woody]

But if the air is coming backwards, wouldn't it go down the chimney pipe, into the firebox, through the damper controls, and out the combustion air intake?

I see what you're thinking, yes, are you smelling it as smoky like the inside of a fire box air? Usually the complaint is the smell if that's what is happening.

 

[Rotro]

Well, considering it's brand new, we hardly even used it before we noticed the living room was freezing. We hadn't even done the paint curing thing yet. So I don't know if we will smell stuff if I let the fire go out. That's a good point though, perhaps the air is coming in from the chase and not down the chimney pipe. Maybe the chimney cap is so loose that air is coming down that way... as a matter of fact that makes more sense considering it's blowing cool air if it's just embers and we don't smell smokey stuff.

You know what, you may have just clued me in on the real problem. When they put up the new chimney, they hired people who only know how to lay brick. They bricked up straight to the siding and I complained showing them I can put my finger into the chase from the outside. Push on the siding a little and my finger can go into the chase. Bugs? Dirt? Air?

At that time I had no idea the fans were open to the chase. They "fixed" it cosmetically with j-channel... and I made them climb down the chase to pull out the siding in the chase. I was worried the J-channel in there would fall over and we'd smell burning plastic for years.

Does that seem like it could be the problem?

 

[Rotro]

I guess my question now is, does a chimney chase suppose to be sealed? If it is, I will have my problem resolved as soon as I can. Perhaps pull off the siding and filling the gaps with fireproof sealant. I frankly don't know why I didn't connect the two things but I suppose I didn't imagine chase air as being part of the systems. Hope I'm not too excited about an easily sounding, and easily doable, resolution...

 

[begreen]

Unfortunately we are just guessing about how this was installed. The one error stated by the installer is the assumption of a copy/paste error. I don't tink so, Lucy. Get written clarification from PE on that subject.

The only way to know how this was installed is to examine it. This may take making an inspection hole or two to see and document the installation. It may not take completely removing the siding all the way up the chase, just enough to get in and have a working area. If this is done, make sure that everything has been installed properly. While sealing, consider insulating the chase, properly and installing an outside air duct with an inverted P trap with a rodent screen on the outside intake cover.