Caulking new water heater?

[rwessels]

I am installing a new Atwood water heater and need advise on what type of caulk (brand) to seal it? I know silicone is out but wasn't sure what to use on the outside of the AS.

[0557]

I use Butyl tape, basically a non curing flexible tape around the perimeter of the hole for the heater. Once you have it rolled on, peel the outer layer of the wrapper away from it, push the unit in,
Bend your edges snug and flush with the edge, tighten the screws, trim the edge of butyl squeezed out with a razor blade (lightly ) clean up with mineral spirits.

[lewster]

Along with the butyl tape, I run a bead of SikaFlex 221 along the top edge of the heater and down the top curved sections. Makes a great extra seal to prevent water incursion form the top. The butyl tape takes care of the rest.