Chimney connection - seems wrong to me, advice, thoughts?

[TheBaron]

So last week, we had a reputable (BBB highly rated) local fireplace shop install our new Jotul C450 insert, which we also bought there. A 'turn-key' install if you want to call it that. We had them come and do a consult, measure up our existing masonry fireplace, and give a price which also included putting in a new hearth, (2 layers micore, 2 layers durock, and I tiled with slate).

Chimey liner setup: They said they needed to order a special 45° elbow to clear my lintel and install the fireplace. It is being connected on one end to the stove, and the other it looks like they attached to the adapter (from the 6' uninsulated ss liner kit), then to the liner. Notice there is no block off plate. I mentioned this to them and they insisted that if they stuff the top and bottom with Roxul, there is no problem.

My observations: a) I hear an extremely annoying sucking noise when the fire gets up to temp and I suspected it is where the liner meets the adapter (which I confirmed by holding a match in this area). b) There is also a screw-hole where there is no screw and air sucks in there as well. c) before the label got burned unrecognizable, the arrow showing the direction of airflow was pointing down. I thought that these guys must know this and no big deal (maybe thats the case). d) the screws look like they are getting a much lighter color of grey, and I'm wondering if they used the SS screws.

My questions: a) Is this setup not done properly, the backwards elbow and air leaking issues make it appear to be an issue? I would have preferred them bring the liner down and connect direct to the stove, and it looks like it is possible. b) Will the elbow cause me problems down the road with cleaning, etc? c) Do I need to worry about dissimilar metal issues here and get the screws changed out? d) Lastly, the block-off plate... I am ok with the stuffing of Roxul up there as long as I don't have draft issues. There is no air leakage back through the chimney that I can detect.

Thanks for the help/advice on this. I really like the stove and it is working well, I just want to get it done right and now is my chance to do so (they come Monday to do the final trim kit and adjustments as well as collect another $2k)

 

[begreen]

Not perfect, but not a bad job from what is visible. It would have been nice if they pulled off the label off the elbow, but don't worry about the direction, it looks correct for this application. If they will come out to squeeze a little furnace cement around the flue collar, have them put a screw in the hole. Make sure that the roxul is packed well in the damper area. It looks like there may be a gap on the right side but that could just be the camera angle.

 

[webby3650]

It looks OK. Like Begreen said, just make sure that that insulation can't fall out. It would have been nice if they used an elbow that was made to connect directly to the flex, but no big deal. It's odd that they had to order an elbow. It's nothing out of the ordinary, it's very rare that an elbow isn't used on an insert.
Are you sure the sucking sound is coming from the fittings? A lot of stoves make a sucking sound that is coming from the primary air intake. Maybe thats what you are hearing?

 

[TheBaron]

Good to know, I thought the elbow was not all that common.

The sucking sound is definately coming from where the flex meets the adapter. When I put a match here it really sucks the flame in too.

It looks OK. Like Begreen said, just make sure that that insulation can't fall out. It would have been nice if they used an elbow that was made to connect directly to the flex, but no big deal. It's odd that they had to order an elbow. It's nothing out of the ordinary, it's very rare that an elbow isn't used on an insert.
Are you sure the sucking sound is coming from the fittings? A lot of stoves make a sucking sound that is coming from the primary air intake. Maybe thats what you are hearing?

 

[TheBaron]

I guess no harm can come of jamming in more roxul as long as its well compressed (I'd imagine its more to block air than insulate).

I had wished that my flue could accept insulated liner, but I'd already had my three wishes last year

Not perfect, but not a bad job from what is visible. It would have been nice if they pulled off the label off the elbow, but don't worry about the direction, it looks correct for this application. If they will come out to squeeze a little furnace cement around the flue collar, have them put a screw in the hole. Make sure that the roxul is packed well in the damper area. It looks like there may be a gap on the right side but that could just be the camera angle.

 

[webby3650]

I had wished that my flue could accept insulated liner

What size is the flue?

 

[webby3650]

Insulating the liner is great, but using Roxul as a block off plate is gonna go a long way. The insulation on the liner really helps prevent creosote build-up more than anything. The block off at the bottom helps keep the heat in the room, not sending it up the chimney. I don't feel that a block off plate is always necessary, but it never hurts and stuffing it with Insulation is just as good as the plate, if it stays in place.

 

[TheBaron]

The liner is a 6" uninsulated 'Magnaflex' SS.

I'd like to get a more premium cap too, this one looks a bit cheap but we'll see how it works over the current burning season.

What size is the flue?

 

[webby3650]

The liner is a 6" uninsulated 'Magnaflex' SS.

I'd like to get a more premium cap too, this one looks a bit cheap but we'll see how it works over the current burning season.

I meant the masonry fireplace flue. It's pretty rare that an insulated 6" liner won't go down a fireplace flue.

 

[TheBaron]

Its a 8" flue tile (square profile)

Thanks for your help!

I meant the masonry fireplace flue. It's pretty rare that an insulated 6" liner won't go down a fireplace flue.

 

[Highbeam]

You sure that stuff is roxul? I've been researching roxul for my barn and it is noy yellow. It comes from basalt which is black and slag which is grey. No yellow. Looks like regular fiberglass there which is less desirable than roxul in this application.

The elbow is needed or else they would have had to cut the steel angle in your fireplace opening. The brush should go right through it but you will feel resistance. Be sure that everything stayed together after brushing.

The elbow isn't evenly seated in your collar. That tells me it is cocked in there and not seated well enough for a good seal. You can try and schmear cement in that gap but it should have been installed square. Try using something that makes smoke like a cigarrette, or incense stick, or firecracker punk to look for leaks. You don't want leaks.

Can that aluminum tape be added at the flex/pipe joint?

 

[webby3650]

Can that aluminum tape be added at the flex/pipe joint?

No, i won't stick after it gets hot.
Try some Milpack, it stays softer than cement.

 

[Lumber-Jack]

Seeing that Roxul hanging down like that looks like kind of a sloppy job, did they leave it like that, or were you pulling some out? Doesn't look unsafe, just sloppy. The idea is to try and pack it tight enough that air has a hard time flowing up the chimney, if they were so sloppy to leave it hanging down like that, I wonder how tight they really have it packed around the flue?
Do you have any pictures of the cap area?

 

[webby3650]

Its a 8" flue tile (square profile)

Thanks for your help!

That's strange, an open fireplace would really struggle on that flue.
Unless there is a big offset, a 6" insulated liner would go down an 8" flue. We have done it lots of times.

 

[Highbeam]

I think that the insulation is not packed around the flue. It is a form of a block off plate and only shoved in about a foot so that it would stick.

 

[PLAYS WITH FIRE]

If you think you have a leak do a smoke test with a match or something.

 

[TheBaron]

For sure its Roxul, I have installed it many times (in walls though).

I tried using a match to test for air leaking in and it is occurring in two areas, where the screw is missing, and where the FLEX meets with the adapter piece

You sure that stuff is roxul? I've been researching roxul for my barn and it is noy yellow. It comes from basalt which is black and slag which is grey. No yellow. Looks like regular fiberglass there which is less desirable than roxul in this application.

 

[TheBaron]

Seeing that Roxul hanging down like that looks like kind of a sloppy job, did they leave it like that, or were you pulling some out? Doesn't look unsafe, just sloppy. The idea is to try and pack it tight enough that air has a hard time flowing up the chimney, if they were so sloppy to leave it hanging down like that, I wonder how tight they really have it packed around the flue?

I haven't touched the Roxul, it was left like you see it (I agree, it looks sloppy)

Do you have any pictures of the cap area?

Will take one in the morning once the sun is back up 8). Will be burning lots of wood between now and then

 

[TheBaron]

When the guy was installing the liner, it was a straight run down to the damper assembly. On the way down it was able to move fairly smoothly, but you could hear it scraping against the sides of the flue tile. When I asked him if a 'insulated liner' would fit, he said they don't have one that will fit my chimney.

Maybe he was just blowing smoke... For an $899 install fee (labour only), you would think that he would do a very pro job. Maybe I'm dreaming there, but he was at the house for maybe 2 hours (and he had a helper)

That's strange, an open fireplace would really struggle on that flue.
Unless there is a big offset, a 6" insulated liner would go down an 8" flue. We have done it lots of times.

 

[TheBaron]

So I let the fire die down last night and started from a cool stove this morning. The sucking noise at the joint wasn't there during the start-up phase. It really only became loud once the fire was really going and the door was shut. I guess it only leaks there when the stove is in the air tight mode of operation (makes sense...)

 

[PLAYS WITH FIRE]

That is the important time! I would get a tube of Rutland furnace cement and smear it with your finger and a mirror around the areas you can't see. The area that you can see I would apply it very nicely and carefully so as not to look like crap. Let it dry for a couple hours, maybe the better part of the day and fire it up. I bet you will notice the stove runs waaaaay different!

The bad about the Rutland is that it will eventually break away, just reapply. The good about sealing it is the stove will only pull air from where it is supposed to!

 

[Lumber-Jack]

I think that the insulation is not packed around the flue. It is a form of a block off plate and only shoved in about a foot so that it would stick.

That's correct, it only goes in a little ways, but it needs to be packed tight enough to compress itself and seal off any areas where air can freely flow through. If it is just lightly pushed into place it, almost certainly, won't compress and fill the gaps. Just like an exterior door needs to shut tightly against it's weather stripping to compress it, where as a loose shutting door, that doesn't compress it's weather stripping all around, will leak like a sieve and allow a lot of cold air past. Of course in the case of this flue, loosely packed Roxul will allow hot air out.

 

[TheBaron]

Here is a photo of the exterior / chimney coming out of the flue tile and the cap (as asked about earlier). I will have to get up there (need a long ladder) and check things out when it gets a bit milder.

 

[Hogwildz]

Insulation stuffed in place, does not stop air flow. A sealed block off plate does. I don't care how tight you try and pack insulation, you will never get the corners or around the pipe tight as you would with a sealed block of plate. Stuffing insulation in there is just plain lazy.

 

[Lumber-Jack]

Obviously a well installed (and sealed) block of plate is preferable to just insulation, but a poorly installed block off plate can leak just as badly, or worse, than stuffed insulation. I would do both myself.
However, if you are going to rely on just insulation, best to make sure it's sealed as best it can be.