Single-wall vs. double for short distance stove connection

[Alexander L]

Hi all! Have been chipping away at the stove install. Not much left to do... install a mantel and connect the jotul f100 to the thimble.

Which leads me to... connecting pipe. Single or double wall. Not sure.
I am going out the back into the wall thimble. The back of the stove will sit 11 inches from the face of the wall tile. About 8 to 9 inches from the thimble connection. A rather short distance.

1) Is there any reason to go with one pipe over the other when it will be such a short horizontal run?
* I see that single-wall requires an 18" clearance to combustibles. Being that I am going horizontal out the back of the stove, and that the center of the stove's rear exit is 18.5" above the hearth plate... makes me think single-wall can not be used for my install. Seems that would put it too close to the combustible flooring that is under the steel hearth plate. Do I have that wrong?

2) I see that some folks install stove adapter/connection that has a damper. The jotul f100 features an air control lever. I assume that this makes another damper in the connecting pipe unnecessary?

Appreciate any insight/advice!
Pics to illustrate install:

 

[bholler]

Yeah if you really only have 18.5 from the floor to the center of the pipe you cant use single wall.

 

[Highbeam]

People add key dampers to the pipe in addition to the stoves draft control. The stove’s control doesn’t always close very far. This is by design so that you don’t run the stove too cool.

 

[Alexander L]

Yep, makes sense to me. Double-wall it must be. Thanks, bh.

So a DVL adapter will connect the stove's flue outlet to Duravent DVL double-wall pipe. Easy enough.
Is an adapter with a damper necessary if the F100 has an air control lever?

*edit: posted same time as Highbeam. Thanks, Hb.

Is it advisable to add a damper for further control?

 

[Highbeam]

Unless your chimney is very tall you shouldn’t need one. It can be added later. I had one and removed it.

 

[Alexander L]

Thank you, Hb. I searched some older posts a bit further and it looks like I don't really need to add a flue damper unless I have an overly strong draft... and I won't know until I am set up and burning. My chimney is about 15' and all on the exterior. Not likely to produce an overly strong draft.

I'll get the regular adapter. Thanks for the info!

 

[Alexander L]

Okay, another question related to stove connection.

I purchased the Duravent DVL appliance adapter. Looks great... but I have a question about the fit.
It fits over the jotul flue collar like It should, but the crimp does not "wedge" itself into the collar.
There is about an 1/8" of room for wiggle at the end of the crimp where it sits in the collar ... sort of a loose fit. Is this okay? Does not "press-in" like I figured a crimped piece would.

I did speak with Duravent tech support, and was told that they are allowed about an 1/8" for connection tolerances, and that the expansion from heat will close the tolerance once burning. She said I could "open up" the crimp a little with needle-nose pliers to make a better fit. Sound like a good idea? I don't know how tight this fit should or should not be.

I can see how this might be okay for pipe going up from the top of the stove, but I am going out the back... horizontal.

I put the jotul flue collar on top of stove just to illustrate fit. This will be a rear exit install. Pics:

 

[Marshy]

If it's not wedging into the collar I would attempt to expand it some.

 

[Alexander L]

Yeah, not wedging at all. Just sort of sits into the collar... like I suppose it should, minus any wedge action.

 

[Alexander L]

Revisiting the install manual, I see that there is a flue collar gasket to be applied to the inside of the flue collar. It is a thin rope of gasket.

I just spoke with jotul tech support... the gentleman says that the included rope gasket should be enough to reduce any gaps/movement, and that I could use a thicker rope gasket if I choose. He said that a tight seal is not critical here at the crimped part, as the system is under negative pressure and will not leak any smoke.

I suppose flaring out the male crimp a tad and a thicker rope gasket (1/2" - 3/4") applied with stove and gasket cement should do the trick.
Any installers see issue with this?

Appreciated!

 

[Highbeam]

Whoa! I had a cast iron hearthstone and found that the appliance adapter was loose but the end of the regular double wall pipe was a perfect fit. I did not use the adapter. Maybe you try it without the adapter,