Call Dometic Cust Svc (they bought Atwood). Give them your RV type and Atwood 15k heatpump and they should know what to do. There are two parts, the new diffuser and a new grill.
I got the parts just to have them, but have not installed because mine does not drip (yet).
I clipped this info out of another thread on the subject.
“Today I also called 800-544-4881 & pressed #3 then press #2 & spoked with Rep. Sharon who was very helpful. Dometic is shipping out 2 newly designed Air Intake/Filter Assemblies consisting of Part #'s 3315930.101 & 3315919.000 & was advised that Dometic will pay for any labor charges to install - she also gave me a confirmation #.”
Our Isata 3 also drips when the filter gets clogged. Once we clean it with water and let it dry before we put it back in, it doesn't drip any more. Chris