insulating entire fireplace/damper w/mineral wool instead of block off plate

[_CY_]

how do you measure the temp of your cat?

temps are measured with original condar Cat thermometer that's calibrated with a digital pyrometer

(broken image removed)

 

[_CY_]

Last year when I got my stove and didn't really know how to burn real well, I called VC technical support and had a nice conversation with someone, I asked about wrapping the insert in a hi temp blanket. I was told that it was not recommend due to the fact that the insert was not designed to burn with it on.....so I decided to let it go and now passing that along to you, you might want to call buck stoves tech support and ask them.
Now that I know how to burn correctly, I am achieving a desireable heat output in my insert room, no lower block off plate, non insulated ss liner in an outer wall masonary chimney.......I thought it was the inserts fault, it was actually mine....

talked to Buck tech support a number of times .. they had no clue what to do for my low heat output issues
idea for insulating entire firebox and damper came from an old time installer .. evidently he had done this exact same thing for other Buck 91 stoves twenty years back. he claimed heat had no where to go after insulating except out by fan and would improve heat output .. he sure was right.

only he used regular fiberglass insulation without backing and with foil back .. he stated where it got extra hot stiffened a little, but otherwise insulation was in good shape after 20 years.

 

[begreen]

Did they make the Buck 91 twenty years ago? I don't know, just asking.

 

[mellow]

I would just add that you should have a digital thermocouple with an alarm just in case so you don't overheat. I have noticed with mine the way I insulated it, it tends to run hotter and I have to keep a closer eye on it and shut it down sooner and with less air. The alarm has saved my butt a couple times this past season.

 

[Hogwildz]

Defeating the purpose of letting heat flow from the insert.
So now your effectively blocking a majority of heat coming from that thing to just the front & a fan.
If they were intended to have all that insulation round them, they would come with it.
There is such a thing as over engineering.
Put a proper block off plate in there and do it right.
Let that heat flow.
Hope it works out for you and doesn't ruin the insert.

 

[bholler]

f they were intended to have all that insulation round them, they would come with it.
There is such a thing as over engineering.
Put a proper block off plate in there and do it right.
Let that heat flow.
Hope it works out for you and doesn't ruin the insert.

I agree totally

 

[bholler]

Ok I will say again I do not doubt that your install is safe but did you tell that fire marshal that although that insulation is ul listed it is not listed for that application? I think that the way you did your install is way more complicated and harder to do without gaining any additional safety over a standard install. To everyone reading this I have to say to always follow manufacturers instructions and always use the appropriate materials. They have been tested for that specific application while others that might seem like they should work were not.

 

[bholler]

Yes but all of that says nothing about being used on a chimney liner so it still is not tested for the application you are using it for. And Yes I have read and passed the CSIA certification test on NFPA 211 and it also states that you need to follow all manufacturers instructions. And every one of those instructions that I have read say that you need to use an approved chimney insulation not just a non combustible one.

 

[Hogwildz]

I'm still wondering how your getting more heat out of an insert that now only has the front surface and fan as the only points of heat to get off that thing.
Ain't no way it is getting more heat out into the room with less surface area exposed.
Most of the heat loss to start with was prolly the heat going up the chimney cavity due to no block off plate to stop it.
But hey to each their own. Don't want to be bothering you.

 

[fire_man]

bholler acknowledged the insulation is UL listed. He is just pointing out that it has not been tested by the manufacturer for that application. Sometimes it's good that someone points out when we stray from manufacturer's guidelines. In this case it may or may not be a problem, but nothing wrong with making the point - that's why we are all here.

Glad it's working out for you.

 

[bholler]

this will be my last post on this subject due to the fact that I will not get my point through to you. and I would just like to point out that in the other thread you did advise the op that

"a little late now for a tip to save $$$ on liner insulation .. then if you are having trouble with heat loss up chimney .. you can insulate entire firebox and damper area instead of a block off plate. https://www.hearth.com/talk/threads/...neral-wool-instead-of-block-off-plate.124737/

you can purchase high temp mineral wool rated to 2000f to insulate entire firebox, damper for about $40 for one bale of mineral wood insulation. which also comes in 1in thickness in long rolls to wrap liner .. enough to do entire liner for about $40-$80.


That is what bothered me if you want to do something in your house that does not meet code (and this absolutely does not because code requires you to follow all manufacturers installation instructions) that is up to you but when you tell others to do the same or represent that way of doing it as acceptable or better that in my opinion is irresponsible.

I am glad it is working for you but I would never recommend it for anyone

 

[Nick Mystic]

All this talk about using this insulation around an insert got me wondering how good a job this insulation does at reducing heat flow. I know you can get R values for different thicknesses, but I don't know what that means in real terms of heat loss or reduction. Has anyone ever tried putting a layer of this rock wool up against the side of their steel stove and feel with their hand or an IR gun to see how much reduction you actually get? I'd be very interested to know.