Harman XXV Top Flue Option - Can I put a 4" or 3" pellet vent pipe inside the 6" pipe?

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dirtduff

New Member
Nov 15, 2010
4
Oregon Coast
Can I attach a section of 4" or 3" pellet stove vent pipe to the top of a Harman XXV Top flue adaptor?

I would like to hide the 3 or 4 inch diameter pellet stove pipe by sheathing it inside 6" diameter wood stove pipe. The text in the install manual seems to be contradictory. It seems that that the "12" piece of 4" pellet pipe" that is included in the kit is supposed to go inside the 6" pipe. But, the next sentence says that the top flue adaptor is not approved for use with pellet pipe.

Note also that I would like to install approximately 1 ft of this 6" pipe with pellet pipe inside it above the Harman stove top before turning 90 degrees and passing through a brick wall behind the stove with 3 or 4" pellet pipe.

Here is the text from page 26 of the Harman XXV Installation Manual-

- "XXV Top Flue Option (Harman Part #1-00-677120)
The Top Flue option attaches to the exhaust on
the rear of the stove, and extends it to the top
with a six inch stub.
This gives the appearance of a wood stove and also
allows venting with existing single wall, connector.
A 12 inch piece of 4" pellet vent is included to act as
an insulator only
. Note: The top flue adaptor is not
approved for use with pellet pipe. It is only tested
for use with chimney connector (6- inch pipe) into
an existing "class A" chimney.
 
If I remember correctly when they installed my stove, that 12 inch pipe just rests on top of the adapter, it only insulates that portion of the 6 inch pipe so you don't burn your knuckles when you open the glass hopper door. It isn't attached per se, its just sitting on there, sort of pressed on. You would have to view the adapter in person to see if you can attach pellet pipe. But based on the wording you quoted, I am betting you would have a hard time getting it approved by a building inspector, or your insurance company.
 
lordgrinz said:
If I remember correctly when they installed my stove, that 12 inch pipe just rests on top of the adapter, it only insulates that portion of the 6 inch pipe so you don't burn your knuckles when you open the glass hopper door. It isn't attached per se, its just sitting on there, sort of pressed on. You would have to view the adapter in person to see if you can attach pellet pipe. But based on the wording you quoted, I am betting you would have a hard time getting it approved by a building inspector, or your insurance company.

Lordgrinz is right on....the 4" pipe sits on top of the top venting kit, inside the 6" pipe. I believe the manual means you are supposed to only use the top flue adapter with regular smoke pipe, and not adapt down to pellet pipe. I dont beleive any inspector would approve the installation if you "bushed down" the 6" to a smaller pipe, making it have the appearance of reducing the exhaust pipe. Also, it pretty clearly states you CANT do that in your manual, which is grounds enough to fail it. Why not just exhaust out the back, not buy the top vent kit, and stay with pellet pipe?

Grinz- your install looks pretty cool...are those doorways on BOTH sides? You did a good job installing in a not-on-center thimble, still getting the stove reasonably centered! Kudos to you or the installer.
 
Thanks for the replies.

I will be putting the vent through the brick wall in the photo on my profile. The brick wall is really an ash pit for the fireplace located upstairs. So, I need to bore the vent pipe through the first brick wall that is seen in the photo. Then pass through about 18 inch void. Then bore through the second exterior brick wall to vent outside. The walls are at least two bricks thick.

Someday the Harman will wear out. When it does I do not wish to bore another hole in the brick wall to accommodate the different vent height. So, I am thinking it best to locate the vent's interior wall thimble as high as possible under the mantle in the photo. The Harman XXV vent is located only 9 inches from the floor. The mantle is 51 inches from the wood floor. I figure about 2 inches of hearth pad will leave me with a total of 49 inches of clear wall under the mantle.

By using the "Top Flue Adapter" I planned to hide the 4 inch pellet pipe. However, today I was quoted $278 for the Harman XXV Top Flue Adapter. Tonight, I am looking for a Plan B. Maybe just come out of the back of the stove with a simple "T", go up 2 feet, and elbow into the brick wall behind the stove to hide the pellet pipe.

Is two feet of vertical pipe long enough?
 

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piping into the ash pit for the fireplace upstairs?! Do you have a way to isolate that fireplace and ensure only one appliance is in one flue?

Beautiful job of finish work there.
 
Dirt Duff......I went through the same thing with my Castille freestanding unit in my basement. I do not like the look of the 3" pipe, it just doesn't look right IMO. I wrestled with idea of a top plate adaptor too, but finally decided to just tee it out of the back, rise 3' to a elbow and then straight through the wall behind it. Then I took regular 6" black stove pipe and "covered" the 3" pellet pipe.

That was 2 years ago and all is well. Not to mention that I think it looks much better as well.

NPCoot
 
Lousyweather said:
piping into the ash pit for the fireplace upstairs?! Do you have a way to isolate that fireplace and ensure only one appliance is in one flue?

Beautiful job of finish work there.

Lousy W,

Yes, the old ash pit is totally separate from the fireplace upstairs now. The upstairs fireplace had a trap door in it's floor. Users could open the door and sweep the ashes into the hollow chamber that is behind the wall in the photo. There was an exterior door on the ash pit that was used to remove ashes. A prior owner of the house covered the exterior chimney with cultured stone, covering the ash pit clean out door. Look closely at the photo and you can see white staining on the lower part of the wall I think this indicates that there is still moist ashes inside the pit. When I bore the pipe through the wall I will try to vacumme out the remaining ash.
 
NPCoot said:
Dirt Duff......I went through the same thing with my Castille freestanding unit in my basement. I do not like the look of the 3" pipe, it just doesn't look right IMO. I wrestled with idea of a top plate adaptor too, but finally decided to just tee it out of the back, rise 3' to a elbow and then straight through the wall behind it. Then I took regular 6" black stove pipe and "covered" the 3" pellet pipe.

That was 2 years ago and all is well. Not to mention that I think it looks much better as well.

NPCoot

NPCool -
That is exactly what I am thinking I will do. It should be cheaper to build my own 6" pipe that purchase the Harman adapter.
Harman recommends at least 3 ft of verticle pipe before the 90 degree elbow. This will make the pellet pipe verticle and elbow visible above the stove. I want to hide that.
Did you cut the 6" pipe to fit the contour of the back and sides of the Castille?
Could you post a sideview photo of your handiwork on the 6" pipe on the back of the Castille?

Thanks
dirt
 
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