I'm looking for a wall cap for my range ventilation system.

My setup:

From the range, ducting goes up 2', takes one 90 degree bend, then stays straight for 18' through a joist space. Near the end of this ducting, I'm using a remote in line fan (Viking VIL900) that will be placed just inside the exterior wall. I've placed a window seat in the room above to allow access for any future maintenance issues. Ducting will be 10" round.

My question:

I would like a wall cap that would allow me to periodically peek through it to see if I have any grease buildup on the fan blades. To facilitate this I'd place the damper on the range side of the fan, not the wall side. The wall that this will be placed on is about 20' tall. The wall cap will be half way up, so it will be fairly exposed to the elements (rain & snow).

Do any of you have any suggestions? (Mfr. & model numbers?) I've seen internet postings for FiveStar's model 441 10" wall cap. It looks to be louvered, but can't decipher if the louvers are movable, or fixed... movable would allow me to lift them up and peek inside as I described above. A fixed hood style wall cap would keep me from peeking inside.

Anyone have any experience with this wall cap. Is it weather / water tight? Any other varieties out there?

If weather becomes an issue with this style, perhaps I could have a local metal manufacturing company make a custome hood to go over it. A few sheet metal screws would allow me to attach it to the louvered wall cap's flanges.

Thanks for you comment in advance.

Jim