[Uhehner]

A good AC tech can add any brand control to your old existing Marine Air Conditioner. They all do the same thing. One relay or solid state relay turns on the compressor, another turns on the fan, a third turns on the pump and lastly one turns on the reversing valve or heating element.
There is no magic. It does not matter if it's digital, or analogue, they all do four functions and can be wired to your old unit. Of course there are bells and whistles to check humidity, run a program, display various values etc but the basic four output functions remain. Just find a good tech, not a parts changer.
Capt. George