Would "insulation only" be acceptable / safe?

[TedyOH]

So.....I did not install a block off plate or insulate the liner last year when I installed my insert... I just lit a match and blew it out, watched the smoke get sucked behind the surround and up the chimney. It's very windy outside right now so I'm sure that has a little something to do with the draft. I do not have a lot of room to install a plate without removing the insert, I was wondering if it would be "ok" just to shove insulation up around the smoke shelf and flue for now? I still need to caulk the top of the chimney / under the top plate as well. My fireplace back wall is in / facing the attached garage so it's really not an exterior, goes up through the second floor, through the attic space above the garage and is finally fully exposed about the last 10 - 12'. My stove runs very hot as it is right now, hard to keep it under 700 (peaks at 700 for 30 minutes or so). Would stopping this extra air still going up the chimney help any, with the kinda high temps?

Thanks.

 

[begreen]

They sound like two different and independent issues. Definitely get the top plate glued down with a good silicone adhesive like GE Silicone II. The block off plate will stop heat from going up the chimney but will not dramatically affect the stove temp. 700F peak is hot, but not overfiring. Adding thicker splits may be enough to drop it down to 650F.

 

[TedyOH]

Yeah, it's secure now with those 4 set screw / bolts in place but I'm sure there's some air leaking around under the lip of the plate and the clay tile.
Thanks

 

[jatoxico]

I was wondering if it would be "ok" just to shove insulation up around the smoke shelf and flue for now?

Better than not. If you use Roxul it can be cut to size and will hold its shape pretty well especially compared to regular fiberglass. Stopping that air flow should help quite a bit.

My stove runs very hot as it is right now, hard to keep it under 700 (peaks at 700 for 30 minutes or so). Would stopping this extra air still going up the chimney help any, with the kinda high temps?

Possibly. Liner just above the stove is very hot when stove is running but cools off real quick too. I was finding that the exposed liner was heating the top so I would get a quick spiking heat-up that I felt was disproportionate to the load. It would then cool down quick and lose secondaries faster. In addition, with the liner losing heat like that it tended to be dirtier. Now the temp is "truer", more stable and liner is much cleaner and the type of soot is better. Since there is a thermal break between the room (and the stove) and the cold open volume of the old smoke shelf and flue, the stove stays hotter longer it puts more heat out.

 

[TedyOH]

OK thanks, I'll cut some and stuff it up there and see what happens...

 

[jatoxico]

Will definitely help with heat retention in the room. As far as the other issue, with the insert you have exposed flex liner that's single wall pipe in an enclosed space. It was causing some spiking temps for me anyway.

 

[TedyOH]

Here's my "insulation only" block off plate. I see no need for the sheet metal plate other than to hold the insulation up there. I found that the Roxul Safe and Sound was "springy" enough to make a good seal around the damper edge. The biggest thing i noticed burning last night is that during the coaling stage, im getting complete burn / ashes from the splits in the very back of the stove, before it was always 50% charcoal / ash ratio.

 

[kennyp2339]

The biggest thing i noticed burning last night is that during the coaling stage, im getting complete burn / ashes from the splits in the very back of the stove, before it was always 50% charcoal / ash ratio.

Bingo - There are many members that swear if you have coal build up that its moisture in the wood, While in some cases that's a reason, in other cases the stove is shedding more heat than what the coals produce effectively cooling them down to a point were build up occurs. I glad that the roxal insulation is working for you.

 

[TedyOH]

Thanks - yeah the standing dead silver maple I'm burning now is reading at 12-15%, moist wood was not my issue for sure. since I have so much extra Roxul I may put a layer in the back with some cement board.

 

[mellow]

I would recommend it if you can.

 

[jatoxico]

Here's my "insulation only" block off plate. I see no need for the sheet metal plate other than to hold the insulation up there. I found that the Roxul Safe and Sound was "springy" enough to make a good seal around the damper edge.

Excellent that will help a lot. The reason for the metal plate is to act as a true air break and it also lets you insulate all the way down leaving as little exposed liner as possible. That first 18" or so of liner will throw tremendous heat which is either trapped behind the surround or gets soaked up by the firebox.

If its an interior install I guess that's OK but especially with my exterior chimney I prefer to keep the flue gases as hot as possible and let the stove do the heating. Same thing with the exposed liner above the damper. The smoke shelf in my fireplace is cavernous. Before I filled that with Roxul all that heat was lost and my liner was dirtier. Temps measured on outside brick back then were quite high but not anymore .

 

[TedyOH]

The smoke shelf in my fireplace is cavernous. Before I filled that with Roxul all that heat was lost and my liner was dirtier. Temps measured on outside brick back then were quite high but not anymore .

I should have bought the infrared thermometer and taken that reading on the top outside brick, I would be curious to see if my temps drop as well, I also will be curious as to see what my liner looks like after this buring year, hopefully not as dirty as last year (not so much of the shiny black crunchies)

 

[jatoxico]

I should have bought the infrared thermometer and taken that reading on the top outside brick, I would be curious to see if my temps drop as well, I also will be curious as to see what my liner looks like after this buring year, hopefully not as dirty as last year (not so much of the shiny black crunchies)

Had to go back and look at my old thread;

...the exterior brick at the level of the smoke chamber (12-18" above stoves top plate) could be as much as 80 F when outside temp was around 30 whereas now it's more like 40 or so.

Whatever your exact temps etc were/are you should see nice improvement.