Duravent woes

[L337Quaker]

Hi all, first time here as a poster. I recently switched from an Englander PDV to a Harman P43. As part of this, I had to change my pipe setup and replace some sections as the Harman has a lower exhaust port. While I've previously had to seal my Duravent piping, I am running into an issue where even with red silicon and heat tape on every joint and seam I am getting smoke leaking from all over when the stove starts. This is a massive issue as I want to use the room temperature settings on the Harman but I can't risk smoke filling the house every time it reignites. I'm willing to spend some money to get this right, what is the best pipe I can purchase for a 3" setup?

The pipe I'm using is all Duravent 3PVL series, my inside run is stove adapter, a clean out T, 2 45° angles, one 6" length, a second T, then a 36" to the outside vertical stack. The reason for the T's is my PDV was very ashy with the pellets I switched to and needed a lot of cleaning.

 

[L337Quaker]

images of my setup, certainly open to feedback on a better method. The thimble is mandatory where it is due to the building construction.

 

[DAKSY]

Can you position the stove at an angle & closer to the thimble? That “horizontal” run is right about at the maximum specified by Harman (48”), & is probably the cause of your smoke issues.
As far as venting, my go-to brand is Excel Pellet Vent. Each section has an internal RTV Gasket & is secured with 3 screws at each joint. Only the stove adapter needs additional RTV.

 

[L337Quaker]

I will look into the ICC piping, thank you! I missed the section in the Harman manual about the length of the run, and it's much different than the Englander so I will also look into changing the angle. I'd prefer the stove pointed straight out from the wall since it's in the center of the room, but if it needs to move it needs to move.