Larry:
You might try pulling the annode rod on your water heater and then rinsing the water heater out. I too had some of the same noises and so the other night I pulled out and replaced the annode rod, and using my new water wand from Camping World, I rinsed out the water heater!
What a mess! You can't believe all of the white grit and hard water deposits that came out. Looked like sand.
After draining and replacing the annode rod, I refilled my tank and turned on the water heater (gas too) and voila - noise is gone!
As far as the a/c goes - I iced up my a/c unit in Tucson last year too. Mike's right, it quit's cooling. :P
I thought it had more to do with the recirculation setting on the a/c unit. When it iced up on me, I had the recirc set on internal. No air flow from outside...
I'll see if that makes a difference in two weeks going to Arizona...
Gregg