Replacing 3-knob/DSA AC controls

Just wanted to pass along some info for others needing to replace their ancient controls.

Last year I replaced the controls for the master stateroom using the Dometic Retrofit kit. It was a simple process with great support from Dometic. It required a small wiring change at the compressor. Everything else was done at the junction strip near the controls.

Knowing more about how the AC is actually wired and controled, I decided this time to replace the salon controls with MicroAir parts, the FX-2 control board and their EasyTouch panel. It also went smoothly and works well. It is also about 1/2 the cost of the Dometic kit.

I acquired the Dometic kit through my local distributor, Annapolis CruisAir. I acquired the Micro-Air parts through Citimarine. Both provided excellent service.

There is one difference between the two worth noting. The Dometic system includes a (off board) relay that allows the controller to read the Hi Pressure switch using line voltage by repurposing one existing wire running from the controls to the compressor unit. The Micro-Air board does not include the relay (it could be added). For the salon/Micro-Air update I did not connect the Hi Pressure switch to the new controller. It was never connected to the old controller either. I have the same functionality as before, but the Micro-Air display will be unable to display a text message if the switch opens so will require more diagnostics to determine a switch open from a compressor fault.

The reason for not connecting the Hi Pressure switch for the salon compressor unit has nothing to do with either controls. In my installation the stateroom compressor unit is mounted above the salon compressor unit, and there isn't space to access the Hi Pressure switch on the salon unit to make the needed small wiring change without raising the stateroom unit and disassembling the shelf it sits on. Since it has functioned wihout being able to 'report' a switch open for 30+ years I can live with it continuing.