Fireplace Problems

[pmsmith2032]

I am hoping someone might be able to help me with our current fireplace. We have the BR-42 which was installed by our builder approximately 7 years ago. Since then, our builder has gone bankrupt so there is no possibility of contacting them directly. We also have no idea who was contracted to do the install. This fireplace box is vented to the outside (directly to the right of the fireplace box; small silver box outside at knee level). From what I've seen I believe online I believe we might have a FOAK combustion kit. A gas log system (Mendocino Oak logs manufactured by FMI products for a vented system...purchased at Menards) was also installed at a later date (the fireplace was originally setup for wood with a gas start). The fireplace is located on the north wall of our house in our family. This family is approximately 25' x 20' with vaulted ceilings. The family room opens up into our kitchen area. The problem we are having is two-fold.
First, a great amount of cold air seems to be entering through the fireplace. This occurs with the flue is closed. On a number of very cold mornings we have awoke to find white frost covering the vents on either side of the fireplace box and up the chimney column and flue (I have pictures). A noticeable draft can be felt entering through these same vents. We have pulled all the siding off the house and insulated (per the installation directions) around the firebox up approximately 12'. We have also noticed that the draft isn't as bad if the combustion air intake is covered (the lever on the face of the box to close the vent doesn't seem to work properly so we have sealed the outside intake with ducting tape). We also use a piece of plexi-glass cut to the size of the opening to seal when the fireplace isn't in use.
Secondly, the fireplace throws off very little heat when the gas is on. Unless I am sitting within a couple of feet of the box, I feel absolutely no heat.
We would like to buy an insert for the fireplace to make it more efficient but it is not possible financially for the coming winter. We also do not want to spend money having someone come out to do repairs or modifications. We know a fireplace isn't overly efficient but our case seems extreme. We are looking for tips/advice on how to improve what we have. Anyway, I have the following questions:
1. Is there anyway to "repair" the lever on the face of the firebox that opens and closes the combustion air vent? I think something maybe bent inside but I don't know how to get to it. The firebox is surrounded by stone. By taping the vent closed permanently , how are we affecting the heat output of the fireplace?
2. Is there anyway to increase the heat output of the fireplace? Would converting back to wood burning help? Other family members have fireplaces with gas logs and they emit A LOT more heat.
3. Would adding glass doors help much?
4. Any other advice/tips/insight that might help us?
Thanks in advance for your help!

 

[DAKSY]

If it's the Lennox model, the unit documentation can be found here:
http://www.lennoxhearthproducts.com/products/fireplaces/bc-br/
From what I can see, it's not much of a heater. If you were to put doors on it & intended to keep them closed,
they'd have to be made with Pyro Ceram & not tempered glass. The tempered stuff can explode with too much heat,
as in a sealed firebox. Once you see the price of the doors with Pyro Ceram, you may faint.
They may cost as much as a small gas insert. You are experienceing the problems of almost every other fireplace installed in a cold climate. You have a big hole in the middle of your house that all your heated air flows out of. It's like having a campfire in your living room. Stay close to it & rotate & you will obtain total body warmth. Move away or stay in one position & you'll freeze.
I'm sorry to say, but your best bet is to tear it out & install a gas fireplace in there - if gas is what you want to burn. You may spend big bucks for a small insert, because that is all that will fit the opening, & it may not give you the heat you want.
A large gas DV fireplace will heat you nicely, even when the power's out. Your call...

 

[pmsmith2032]

Thanks Daksy. What is the difference between an insert and a direct vent (I'm assuming that's what you mean by "DV")?

 

[DAKSY]

Thanks Daksy. What is the difference between an insert and a direct vent (I'm assuming that's what you mean by "DV")?

Actually, they are BOTH Direct Vent (DV) units, but due to the size of the existing opening, any insert you put in there will be small & the smaller ones generally (not ALWAYS) have less BTU insput & therefore put out less heat. If the old wood box is removed, then a LARGE DV unit can be installed PROPERLY. It will look a LOT nicer & will give a LOT of heat.

 

[pmsmith2032]

Thanks! Do you have any idea what kind of price range both of these options would be? Would the stone face be affected if we took the old box out? In both options, the old chimney is no longer used, correct? Are there any issues with carbon monoxide?

 

[DAKSY]

The price for the insert would be less than the tear-out, obviously, so the cost of the new unit & venting - which will use the existing chimney- will be based on the particular model that fits. You have gas line installed & gas logs generally require higher BTU inputs than DV units, so that part of the job should be inexpensive. You may get an insert installed for (ballpark) $3 - $4k. If you go the tear-out route, you're talkin 4 hours before they even get to the install part of the job. It sounds like the existing box is on an external wall, so your stone should be salvageable, as the crew will remove the siding, plywood sheathing & cut the studs to get the old box out. The chimney will be removed & any holes to the outside will be sealed. That part of the job is another 4 hours or more, so a ball park figure for that could be $6 - $8K depending on the unit you choose. Not cheap EITHER WAY - but in the long run you'll be happier & warmer & it'll start paying for itself almost as soon as you start using it, by keeping the heat in your house. Both are sealed combustion units & the danger of CO is nearly non-existent, as long as the glass is secure.

 

[pmsmith2032]

Thanks. Looks like we'll have to start saving for next year. What size insert would actually fit inside our current box (it's the BR-42). In the meantime do you have any tips on what we might do this winter with what we have? Switch to vent free gas logs with the damper shut (I contacted Lennox and they said I could)? Switch to wood?

 

[DAKSY]

Thanks. Looks like we'll have to start saving for next year. What size insert would actually fit inside our current box (it's the BR-42). In the meantime do you have any tips on what we might do this winter with what we have? Switch to vent free gas logs with the damper shut (I contacted Lennox and they said I could)? Switch to wood?

To determine what will fit, you will need the actual dimensions of the current opening, or if you are looking at certain Heat n Glo inserts, how much of the inside of the current box can be "gutted" to give you MORE room. Then you will have to go to a hearth shop & talk to the sales folks. My tip would be to either seal it off completely or see if you can find a dealer who has a credit/instalment plan. I would avoid ANY unvented products. You mentioned CO worries in an earlier post. What do you thing unvented units put out as a normal by-product of the combustion process? If they are unvented, where does that by-product go?

 

[pmsmith2032]

Thanks again! If we converted it back to wood, would we get more heat? We don't use it often (maybe once or twice a week), like the smell of burning wood, and don't mind the inconvience/mess. We converted it to gas as soon as we moved in so have no idea if the wood would generate more heat.

 

[DAKSY]

No. With wood you may get more WARMTH but not more HEAT. All of your HEAT will go up the chimney, no matter what your fuel is. The efficiency of your fireplace is about MINUS 10 %...

 

[pmsmith2032]

So if I understand correctly, both gas and wood are extremely inefficient. The wood would emit more heat and "feel" warmer but in a whole house efficiency prospective It would be just as wasteful (I'm assuming because the hot air in the house is being " sucked up" the chimney).

 

[DAKSY]

So if I understand correctly, both gas and wood are extremely inefficient. The wood would emit more heat and "feel" warmer but in a whole house efficiency prospective It would be just as wasteful (I'm assuming because the hot air in the house is being " sucked up" the chimney).

In an open fireplace, yes. You need SEALED combustion for efficiency.

 

[pmsmith2032]

Thanks! Attached are some pictures of the fireplace:

 

[pmsmith2032]

And a few more:

 

[DAKSY]

Typical factory-built woodbox. IMHO. the best way to get heat would be to install a gas DV insert. You will be much, much warmer & glad you did. In a 42 " box, you can get a fairly decent sized unit & the co-linear vent tubes will be insulated in the damper area & below the cap. You shouldn't have any more cold drafts & you will like the heat & ambience from the insert. Like I said in a previous post, coupla grand minimum.

 

[pmsmith2032]

Thanks Daksy. I think we'll convert back to wood (we still have the gas ignitor for wood that was installed when we first moved in) and save for an insert next year. Have a great weekend!

 

[pmsmith2032]

One other thing I forgot to metion was that a number of years ago we removed the outside siding and there was absoltely no insulation. We added styrene insulation (made braces to make sure it didn't fall against the firebox) up as far as we could reach. Now I'm wondering if we need to insulate up even higher and need to insulate the pipe leading to the combustion kit. From what I can remember there was a 2x4 frame maybe 12' (two story house) or so up the chase that surrounded the chimney but I can't remember if it was insulated or not. I would imagine if we insualted up to this point and then insulated the box it might help more? I would think that all wood and insualtion must still remain 1" from the chimey pipe (I don't remember what the framing looked like) so there would still be a gap?

 

[DAKSY]

What I do when I install one of these ZC wood units is insulate the outer walls up to about 4'. That of course depends on the height of the ZC unit, so you may have to go higher, maybe 6 or 8'. At that level, I install a horizontal band of 2x4s with 2 additional 2x4 braces 16" in from the shorter end pieces. I can't draw it here, but if your chase is 4' x 2' inside dimensions, you would cut (2) 2x4s at 48" & (4) at 21".
A piece of drywall or plywood is then laid across that band, forming a deck, with a square hole for the approved firestop in the middle. Then the entire deck is insulated with unfaces insulation to within 2" of the venting. Aluminum tape is used to seal the firestop to the venting. It's not perfect, but it's better than nothing. Hope you're able to make sense of that...

 

[pmsmith2032]

Thanks! That's perfect because it will be A LOT easier than trying to reach up over 12-15'! Do you think it will help? Kind of like the attached picture on the right?

We thought that the combustion air kit wasn't closing but could the air we're feeling actually be because of poor insulation. The cold air seemed to come out the bottom vents. We took a hairdryer outside and blew it inside the air combustion kit. Then my father listened and felt for air coming through the vents inside. We didn't seem to notice a difference with the air combustion lever open or closed. Maybe I'm just not understanding how the air combustion kit works?

 

[DAKSY]

Thanks! That's perfect because it will be A LOT easier than trying to reach up over 12'! Do you think it will help? Kind of like the attached picture on the right?

Yep. If I knew about that pic I coulda saved myself a WHOLE lotta typing! Like I said above, it ain't perfect, but it's better than nothing.
Something else I'd do is to seal EVERY seam with either aluminum tape or caulk. You can't get it crab's a$$ tight, but you can cut down on MOST of the drafts...

 

[pmsmith2032]

We thought that the combustion air kit wasn't closing but could the air we're feeling actually be because of poor insulation. The cold air seemed to come out the bottom vents. We took a hairdryer outside and blew it inside the air combustion kit. Then my father listened and felt for air coming through the vents inside. We didn't seem to notice a difference with the air combustion lever open or closed. Maybe I'm just not understanding how the air combustion kit works?

 

[DAKSY]

We thought that the combustion air kit wasn't closing but could the air we're feeling actually be because of poor insulation. The cold air seemed to come out the bottom vents. We took a hairdryer outside and blew it inside the air combustion kit. Then my father listened and felt for air coming through the vents inside. We didn't seem to notice a difference with the air combustion lever open or closed. Maybe I'm just not understanding how the air combustion kit works?

What happens is that in an external chase, your metal firebox is sitting OUTSIDE the warm envelope of your house. It gets cold. When warm air hits that cold box, it'll flow in reverse thru the fireplace & exit the bottom. That's the cold draft you're feeling. When you burn wood, the box is supposed to allow cold air to enter the bottom of the box, get heated and rise. When it exits the TOP of the box it's warmer than when it entered. It really doesn't HEAT as well as a sealed combustion chamber (woodstove) but it'll give you a little WARMTH.

 

[pmsmith2032]

Makes sense. So I should still insulate around it thought, right? Do you think the air combustion vent is working properly from my description? If I open the siding, can I take off the piping leading from the box to the outside vent and maybe see if something is bent/stuck inside the firebox that way?

 

[DAKSY]

Makes sense. So I should still insulate around it thought, right? Do you think the air combustion vent is working properly from my description? If I open the siding, can I take off the piping leading from the box to the outside vent and maybe see if something is bent/stuck inside the firebox that way?

Yes. Insulate & sheet rock the interior of the chase. I believe (& don't hold me to this) that the combustion air comes in thru the slots in either side of the fireplave opening. They are visible in the pix you posted. The are to the right of the rating plate. It may be that it only enters from the side that the air vent outside your house is on. I have no idea what the inside components look like in that particular model, so I don't know what you might find...Sorry

 

[pmsmith2032]

Thanks. Is the sheetrock necessary? When we originally insulated part of this we did the following:

1. Removed vinyl siding and OSB.
2. Nailed wood braces (1x4" if I remember correctly( to the back side of the 2x6" framing (between the 2x6 framing and the firebox). These braces were nailed horizontally and spaced every 3 or 4'.
3. Placed styrene insulation in between the 2x6s.
4. Reinstalled OSB and vinyl siding.

So basically the styrene insulation is sandwiched between the bracing and the OSB.