No reason to fix what ain't broke.......:B
Until the tank leaks why replace a perfectly good water heater.
Surface rust is not unusual. The combustion chamber is a heavy walled 'U' tube.
Swapping from a SW10DE to a SW10D will be easy....no 120V AC to connect (just tape off/secure and leave AC CB off----tape over it for notation).
Still have to connect DC wiring and propane gas line.
Of course when you do replace it with a propane only......it won't work on propane and then you have no AC option.
That's one thing I like about Suburban vs Atwood. Separate t-stats/controls for AC & Gas where Atwood uses same t-stats for both.
So if problem is t-stat neither options work.
I like options!
Is it time for your medication or mine?
2007 DODGE 3500 QC SRW 5.9L CTD In-Bed 'quiet gen'
2007 HitchHiker II 32.5 UKTG 2000W Xantex Inverter
US NAVY------USS Decatur DDG31