Did installer use the right silicone sealant?

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kbrown

kbrown

Feeling the Heat
Oct 19, 2008
297
SE, Michigan
Just had our Napoleon 1402 installed last week; just waiting now for the door. In the meantime, looking at the job, I noticed they used silicone to seal around the area where the chimney flex meets the vent on the insert. It is secured with screws, but they added what they claim is high temp silicone which is good to around 600F. They also used fiberglass insulation to seal around the pipe where the damper was removed. I don't think the fiberglass will be a problem, but my question is the silicone. Should I try removing what they put in and replace it with high temp mortar to seal around there or is it ok? If I should remove it, whats the best way and not damage the flex pipe/connection? The installer has been doing these installs since 1986 but second opinions never hurt.
 
heatit said:
Just had our Napoleon 1402 installed last week; just waiting now for the door. In the meantime, looking at the job, I noticed they used silicone to seal around the area where the chimney flex meets the vent on the insert. It is secured with screws, but they added what they claim is high temp silicone which is good to around 600F. They also used fiberglass insulation to seal around the pipe where the damper was removed. I don't think the fiberglass will be a problem, but my question is the silicone. Should I try removing what they put in and replace it with high temp mortar to seal around there or is it ok? If I should remove it, whats the best way and not damage the flex pipe/connection? The installer has been doing these installs since 1986 but second opinions never hurt.
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The silicone around the flex pipe & outlet of stove is going to burn off and stink to high hell. They should have used furnace cement. While fiberglass does not burn, it does contain formaldehyde and does melt at a certain temp, I do not know what temp but I think its posted on the forums here somewhere. F/G also might sag if its a big span, and does not block air flow like a block off plate does. You should have requested a proper block off plate which should have been sealed with the silicone around the perimeter where is contacts the walls and furnace cement around where the liner comes through.
 
I second hogwildz...why use a product good to a 600* temp that is likely to be reached at some point when furnace cement would have performed the same function without any concern of burning up? Also - not sure what brand of silicone they used, but "good to around 600*" tells me it can almost make it to 600* before melting. What happends when you park it at 400* for an hour, or 500* for 20 minutes? Call the installer, ask what exactly they used, and look it up. If they've been doing installs that long and using this product for a chunk of that time, maybe it is exactly what they should have used. If they've been in business that long I'd like to think part of it is because if the silicone burns up, they'll fix their mistake...but never hurts to second guess if you don't feel safe with it.
 
The installer says it was Rutland. I stopped in the local fireplace shop and they also had that same brand; but did agree it probably will shrink down. The tube says it is good for 450F continuous. I do have a tube of furnace cement and was going to use that but it does not say anything about using it to secure metal/metal joints. Home Depot didn't have anything as I checked there on the way home from the fireplace shop. Good news is we got the door today; although the gasket had fallen off around the bottom of the door. Had gasket sealer on hand so we just sealed that back on and hoping to fire it up later tonight with small fire to begin curing the firebrick. Think the silicone that's there will be good enough for the beginning fires? Oh yea, we picked up a stove thermometer from Home Depot; saw from the forums that is a must have. This site is great!
 
The cement is not to "secure the liner". The srews are doing that job, plus the weight of the liner. The cement is to seal any gaps etc.
The silicone rated at 450 or even 600 is going to smell, I'd put money on it. That liner is going to see higher than 600 temps down around the stove outlet/liner connection when stove is full steam chugging along.
When you smell the silicone, you see what I mean. When you decide to scrape it off and reseal with the furnace cement. Clean the oils from the silicone off real good, or the cement will not adhere.
Sprayable brake cleaner and even rubbing alcohol work well. But you need to get the Silicone itself off then clean any oils left off.
Now for adhering a door gasket, silicone works great IMO. Done both ways, and I'll stick with the silicone. Just keep in mind, anything that protrudes past the gasket burns off, but not biggie, whats behind the basket will hold great.
 
Hogwildz said:
BrotherBart said:
Take a look at this thread. And then get that crap off of that flue collar. :coolsmirk:

https://www.hearth.com/econtent/index.php/forums/viewthread/31027/
Click to expand...

FF sakes!!!!!!!!!! I spent all that time typing, and could have remembered to refer to that thread. Damn, even for an ol fellar, your quick to think pappy .
;)
Click to expand...


hog how are ya !!! haven't heard from ya!!

bb you have a great memory!!!

now if you or hog wanna "donate one of those monster stoves so i can "test" them
 
iceman said:
Hogwildz said:
BrotherBart said:
Take a look at this thread. And then get that crap off of that flue collar. :coolsmirk:

https://www.hearth.com/econtent/index.php/forums/viewthread/31027/
Click to expand...

FF sakes!!!!!!!!!! I spent all that time typing, and could have remembered to refer to that thread. Damn, even for an ol fellar, your quick to think pappy .
;)
Click to expand...


hog how are ya !!! haven't heard from ya!!

bb you have a great memory!!!

now if you or hog wanna "donate one of those monster stoves so i can "test" them
Click to expand...

Still here, still breathing Ice. I ain't giving neither of my stoves up! Not even pryable from my cold dead hands ;)
Besides, you already have one monster. Hows the Summit burning for you?
 
This stuff worked well for me,

DAP High Heat mortar (ASTM E-136 Rated) Resistant to 2000Deg F.. Got it at Lowes, the HD by me has the same in Rutland brand. I found this stuff to be much better than the furnace cement in the big tub.. It cures rock hard with heat applied and stays firm even with some expansion and contraction. For me the furnace cement cracked and fell apart around the flue collar, this stuff is holding well after 2 months..
 

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That is what we are going to do. I have a tube of Harvey's furnace cement that I had forgot I had down in the basement! It is good to 3000F. I had used some before many years ago when sealing around a new exhaust pipe for hot water tank. We have been running small fires in the stove to cure the brick; nothing seems to be hotter than around 350F. Hopefully that will allow us to get the silicone out of there a little easier after a few more of these hot/cold cycles and put in the furnace cement. Overall still happy with the Napoleaon but the control mech for the blower was not installed very well, it has a lot of slop when they put the nut on to secure it to the unit.
 
For a wood insert they should not have used silicone on the vent OR fiberglass in the damper. Both are not allowed.
 
I agree with the silicone not being correct, but for the fiberglass in the damper area; well maybe everyone can help me out understand why you can't or shouldn't vs a plate. Here is my view: you have a continous liner in place where it's sealed off on the top of the flue by the top plate. At this point the chimney is sealed from outside air and with the removal of the damper, you now only need a method to keep your home heat from heating the space in the chimney. So, using the fiberglass to fill the void in the damper area around the liner would seem ok. If it's a question of the fg melting, well that would mean you need at least 1200 degrees to start that process and for that matter, what is the material used when insulating a chimney liner....a fiberglass blanket isn't it? I would understand the reason for the block off plate if you didn't have a full length liner since now your talking possible fire back into the house in the event of a chimney fire, but unless your liner is not a continous piece then that risk is negated, no? Our township follows the national building code and I just can't seem to find any reference to the mandated use of a blockoff plate. I am certainly open to change if someone can point out a code requirement for my area (Commerce Twp, MI). I would really like to hear from others who have a similar install as mine and see what problems, if any, they have had. I am really at odds with this whole thing.
 
heatit said:
I agree with the silicone not being correct, but for the fiberglass in the damper area; well maybe everyone can help me out understand why you can't or shouldn't vs a plate.
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Because it probably says not to right in the install manual, and if it doesn't it should. Its not allowed.

what is the material used when insulating a chimney liner....a fiberglass blanket isn't it?
Click to expand...
No, its a ceramic fiber blanket, a listed non-combustible (which fiberglass is not)

Our township follows the national building code and I just can't seem to find any reference to the mandated use of a blockoff plate.
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Because its not required. You only need to seal either the top OR bottom with a full liner install. Usually the top is sealed with the top plate.

---

I can only tell you the facts, people can do whatever they want. Is it safe?... maybe... does it comply with industry standards?... probably not.
 
Why use any kind of cement?

If that sucker is drafting you're fine? Add a little creosote, and all gaps are sealed. I haven't used any cement with my stove insulation and there are no leaks at all.....
 
If your getting creosote at the stove outlet, there is something seriously wrong.
Most seal for the added precaution & pc of mind. No gap is better than a gap etc.
 
Hogwildz said:
If your getting creosote at the stove outlet, there is something seriously wrong.
Most seal for the added precaution & pc of mind. No gap is better than a gap etc.
Click to expand...

My stove pipe fit tight into the sleeve in the back of the stove. Ran a 2 screws through through the sleeve and into the pipe and that was the end of it. Manufacturer certainly didn't recommend sealing it in any way shape or form.
 
sl7vk said:
Hogwildz said:
If your getting creosote at the stove outlet, there is something seriously wrong.
Most seal for the added precaution & pc of mind. No gap is better than a gap etc.
Click to expand...

My stove pipe fit tight into the sleeve in the back of the stove. Ran a 2 screws through through the sleeve and into the pipe and that was the end of it. Manufacturer certainly didn't recommend sealing it in any way shape or form.
Click to expand...

Good for you, glad it worked out for you.
 
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