Harman Accentra Insert re-piping with ICC Excel

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New Member
Oct 15, 2020
Good Evening,

I'm replacing a short run of Duravent (rusted on me) with ICC Excel piping. I have a few install questions:

1) My insert is currently installed in a zero clearance box. It doesn't have an external fresh air supply but is instead pulling from the house. Is this an issue that I should correct by adding a fresh air intake? Keep in mind it was professionally installed ~10 years ago without a fresh air intake.
2) If I install a fresh air intake, how would I handle not being able to put the intake >4' from the exhaust? In the picture below, I can only go so high with the vertical stack without obstructing the view from the window. The plan was to go as high as possible on the vertical run and use a thimble with the integrated fresh air port if absolutely necessary.


Specifically dealing with the pipe, I have fairly tight parameters to fit within the opening from a previous gas stove roughed in opening in the wall.

1) Can I use a slip length (ICC 4PLA6) directly attached to the Pellet Stove Adapter (ICC 4PAS)?
2) Can I use a slip length (ICC 4PLA16) directly attached to a 45 degree elbow (ICC 4PE45)?
3) Do I need to attach each section with screws or screws and silicone? It's my understanding that only silicone is required on the adapter to the stub on the stove.
4) On the attached image of the stove adapter, which side actually fits over top of the Harman stub kit? I have to order another one and want to have everything planned out. I think the "A" side goes toward the stove and is then screwed on/silicone applied. Is this correct?
5) Is this Excel pipe worth the cost. Including the thimble, stove adapter, jet nozzle, 2 x 45 elbows, 1 x 90 elbow, 1 x 6" slip length and 1 x 16" slip length all in 4" diameter I'm at right around $600. Does that sound about right?

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Thanks in advance for the help all!

Last edited:


Full Time RVer
Staff member
Dec 2, 2008
Wherever we're parked
I would add the OAK. You can use the Harman thimble WITH the OAK in it or
you could locate it on the lower part of the short sidewall of the "doghouse."
All you ICC pellet vent needs to be screwed together, including the "slip" sections,
but you only need RTV on the adapter.
Any section may be assembled to any other section so the location of the slips is
a non-issue. Put them where you need them.
All the other vent sections already have an RTV O-ring in them.
Can't speak to the price you quoted, but I WILL say that ICC makes a quality product.
Both of my Harmans have ICC pellet venting...