# caulking/sealing stove pipe fittings



## joed2323 (Nov 11, 2014)

I'm in the process of installing a pellet stove in my house.

I'm going to test fit my piping to make sure its how I want.

I want to go back over and seal each of my connections with hi temp caulking or some kind of tape.

My question is should I lay a bead of caulk in where the rope lies then lock it together and go back over the outside of the connections with some more caulk or tape?

Should I still run some self tappers into pipe or is this not needed with the use of caulking?

Also I've heard some ppl say to pull the rope closer to the edge with a pick or similar tool then connect the pipe, is this a necessary step?

 Is this overkill? Sorry I think I'm over thinking this but I only want to do this right once with out headaches down the road.


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## JDenyer236 (Nov 11, 2014)

Apply high temp metal or silicone tape to the joints on the outside of the pipe. If you apply it internally you will never get that pipe apart again. If you are using the pipe that twist together you shouldn't use screws, you risk puncturing the inner pipe and it's not necessary. No need to move the rope gasket. Assemble and tape up the seams and done.


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## joed2323 (Nov 11, 2014)

Whats the best method for sealing the pipe that connects onto the stove? I can push it onto my stove fairly easy so I'm pretty sure it will leak also If I don't apply some type of sealant? .
Would hi temp caulk work for this spot? If tape is a must I will need to remove the back panel peice in order to have enuf room to get tape around the fitting

I'm gonna run my piping with a 12" peice off the back of stove horizontally then elbow and up vertically.

To me this is the best method to keeping most of my joints outside of house to cut down on areas that could leak, this way I should only in theory have two spots in house that could leak smoke


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## funflyer (Nov 11, 2014)

I used duravent after talking to several installers. Most recommended to seal both inside and outside joints with high heat RTV. I was wondering about taking the pipes apart sometime in the future for cleaning so I put 2 pieces together with RTV and tried to take them apart a few days later. By hand with gloves on it was not going to budge so I used 2 strap wrenches and they turned apart easily. I also used the strap wrenches to assemble the pipes, made it much easier. I bought the wrenches at Harborfreight for about 10 bucks for 2. They have rubber straps and grip the pipes nicely. I also sealed the adapter that went on the stove with RTV and used a hose clamp to tighten it down. There are 4 joints inside my house and all are leak free and tight. When the stove is operating, there is not even a whiff of smoke smell in the house.


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## JDenyer236 (Nov 11, 2014)

At the stove exhaust to pipe junction I would use hi temp silicone caulking, run a bead around the inside and outside to form a good seal. I personally like the tape for all other joints, it's easily removable should you need to do so in the future.


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## joed2323 (Nov 11, 2014)

With my stove the exhaust vent is horizontal so I originally thought the best way to vent would be straight out 12" then to a elbow and straight vertical 3-6' ending with termination cap.

Would their be any benefit if I went with 90 elbow off the stove going vertical 3-6' then another 90 elbow and outside with termination cap??


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## TonyVideo (Nov 11, 2014)

I went straight out only about 2 feet with an angled piece down with a grate on the end to keep critters out. However on the outside my exhaust is 4 feet above the ground so I could do it.


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## Bioburner (Nov 11, 2014)

joed2323 said:


> With my stove the exhaust vent is horizontal so I originally thought the best way to vent would be straight out 12" then to a elbow and straight vertical 3-6' ending with termination cap.
> 
> Would their be any benefit if I went with 90 elbow off the stove going vertical 3-6' then another 90 elbow and outside with termination cap??


Cleaning issue with 90 at stove. Would-should be a cleanout tee.


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## TonyVideo (Nov 11, 2014)

T at the end of the horizontal with a cap on the bottom part of the T. Open the cap an run a brush straight down from the top to clean.


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## joed2323 (Nov 11, 2014)

Bioburner said:


> Cleaning issue with 90 at stove. Would-should be a cleanout tee.



Yes I see it will be an issue without one...
I better scrap that idea using the elbow and pickup a clean out tee instead of 90

Also is it a judgment call on how high my vertical length will be once I clear the wall thimble and up?

I know they recommend at least 3 foot rise, is taller the better answer with vent piping?

If 3 foot works why go 6 feet? I'm guessing its to clear whatever obstacles may be in way?


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## Wilbur Feral (Nov 12, 2014)

Personally I use RTV (high temp silicone) on inner pipe EXCEPT those that will need to come apart for cleaning (not all do).  On those that need to be disassembled silicone tape on outer joint works great. With regular Duravent, I have had to RTV even the outer joints of their factory seals on 45's and 90's. 

For vertical rise, taller is better in terms of developing natural draft, so it's a matter of clearances and cost.  Personally I have a 4' rise after horizontal and it works well.


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## joed2323 (Nov 12, 2014)

Is their any benefit to having the terminating cap above the gutters of my roof? I live in a ranch and its windy here all the time in north dakota, Will i run into issues staying below the roof line with wind/draft?

I picked up the duravent pellet stove kit because its all i could find, and i planned to seal every joint regardless


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## Bioburner (Nov 12, 2014)

Will help keep your siding cleaner. Negative, its a pain to brush out the venting and do a leaf blower treatment. I know what wind is as we live on the southeast side of the Red River Valley.


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## smithg (Nov 12, 2014)

I use the rtv on inside joints that don't need to come apart to clean. Therefore, I don't have any rtv on the appliance adaptor or my last connection before going through the wall. I see no reason to rtv outside joints. Do not screw the duravent pipe, it will destroy it.


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## joed2323 (Nov 12, 2014)

smithg said:


> I use the rtv on inside joints that don't need to come apart to clean. Therefore, I don't have any rtv on the appliance adaptor or my last connection before going through the wall. I see no reason to rtv outside joints. Do not screw the duravent pipe, it will destroy it.


Thanks. I will only caulk joints that I do not want leaking. I have two joints inside house that I have caulked tonight. Tmrw I'm hoping they will be cure for me to fire up my stove other wise it will be Friday at the latest


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## Larry0314 (Dec 15, 2014)

For*Pellet stove venting: *

*"Pellet stoves have to push* the exhaust air through the vent pipe with the stove's exhaust fan. With less restriction your pellet stove will breathe easier and burn more efficiently. First let's clarify the word restriction. Restrictions come from several different items.

*1.  45 degree elbows*

*2.  90 degree elbows*

*3.  Horizontal distance*

*4.  Vertical distance*

*5.  Elevation where you live.*

*A rule of thumb equation we are using has been adopted by most pellet manufactures. The equation is called the sum of Equivalent Vertical Length (EVL). All of the above mentioned venting restrictions have been assignedEVL values as follows:*

*1.  Each 45 degree elbow = 3 EVL*

*2.  Each 90 degree elbow and Tees with cleanout = 5 EVL*

*3.  Each foot of horizontal run = 1 EVL*

*4.  Each foot of Vertical run = 0.5 EVL*

*5.  Elevations above 3000 ft with an EVL of 7 must adapt to 4 inch vent pipe.*

*If your installation is below 3000ft, we would need to do some math. The rule of thumb equations is that if the sum of the EVL is 15 or greater, then the pellet vent pipe would be increased to 4 inch diameter pellet vent pipe." http://nevelsstoves.com/pellet-stove-venting.html*


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