eternabond and roof AC install

[Pyrofish]

Sooooo, I'm about to install my Dometic rooftop unit, and I see the install requires pulling down on the foam ring around the AC. I'm thinking of using eternabond double putty under the foam. Anybody see any potential problems with this?

I'm also planning to install my Fan-tastic Vent using that tape too. That product says to use the included foam ring as the install sealant. I'm thinking the putty will be better.

Any advice?

What a charley fox-trot BTW. I bought my AC used, and never even thought about the piece inside. The vents, the thermostat, etc. So it's a return, a supply, and some wires hanging out of my roof till I get something to hook to that harness.

[Shadow Catcher]

My suggestion is do not rely an any one method of sealing. Use the tape and then silicone sealant.
Are you certain this thing actually works?
You can wire it using a conventional thermostat and controls once you have the wiring diagram.

[8ball_99]

Just use the foam ring. You don't need or want to use silicone or putty. If the Foam on the AC looks bad replace it. As long as the roof is clean the foam will seal NP.

That closed cell foam gasket that comes with the vent will work fine. But with RV roof vents, well really any kind of trim on a RV you can't beat putty tape. Use butyl putty tape not the standard stuff.

[bdosborn]

Eternabond is sticky stuff. I don't think I would use it on the A/C because you would get ONE chance to install it correctly. And you would have a heck of a time if you needed to get it off and clean up the eternabond. Also, eternabond doesn't stick to silicone caulk.

Bruce