Hey Mhokenberg. I have a Jacuzzi Echo/Essence hot tub and I ran into a similar issue you did last fall. My control panel is a Balboa model and I had to have some parts replaced on my heater. The repair person unplugged all connections to the heater, including my control panel. When he plugged everything back in the water started circulating and we figured everything was good. It wasn't until later I came outside and noticed my water hadn't heated up at all and I was getting the same error messages your were. I was totally confused and didn't understand. After looking at my heater where the control panel plugs in with the phone jack looking connection, I noticed I had two slots I could plug it into. On a complete blind chance, I unplugged from the jack it was currently in and plugged into the other one. Bingo! The water started circulating like usual and my heater came on and I could finally get a temperature reading again. I figure the repair guy plugged me back into the wrong jack. Not saying this will correct your issue, but it's something to at least try if possible.