I have a 1998-2002 Echo Z-135 tub with a Balboa R574 board and a 2-button Top-Side LCD Control Panel. I purchased the tub used, have had it running for about 8 months, and it's ran fine. It is running on 240v.

Last evening I went out to sit on the deck and heard the circulation pump cycling on and off about every 20 to 30 seconds. The water was warm, but not completely up to temperature. The circulation pump is moving water out of the jets, so I know that the pump is working and unless the water temp was just residual, I ASSUME that the heater is working.

On the Control Panel, typically it shows what the current temp is until you push the temperature button, then it shows the 'target temp' and with each push of the button it either increments the target temp up one degree (up to 104) or down one degree (down to 80-something). Once it reaches the max or min target temperature, pushing the button again changes the direction of the cycle. Once you let off of the button for a couple seconds, it shows the current temp again.

However, now it just shows a number in the target temperature range cycling continuously up, then down, then back up nonstop. Pushing either button does nothing to stop the cycling of the display nor does it turn on the high pump nor will it turn off the cycling of the circulation pump.

From what I can tell, the circulation pump and heater are turning on during the range when the cycling of the number on the display is above the 'current' temp of the water (of course, because I can't see the 'current' temp on the readout, this is theoretical, as I'm trying to 'guess' the temp with my hand), leading me to believe that the thermostat is still working, and that the circuits that check between the controller and the current temp are still working. Anyone have any idea where to go from here? Thank you in advance for the help.