I did some more troubleshooting of this problem. When attempting to run the heater, I found that the green power light stays lit continuously (as it should), but the display is reading "OFF". After 30 seconds or so, the Pressure Switch green light comes on for only a few seconds. During this brief time, the screen display shows "- - -". Then, the Pressure Switch green light goes out and the screen displays "OFF". After another 30 seconds or so, the Pressure Switch light again turns on, the screen shows "- - -". After a few seconds, the Pressure switch light goes out and the screen again shows "OFF". This process keeps repeating, but there is no error code.

Does anyone have an idea about what could be causing this problem or what needs to be fixed? It would be much appreciated.

I replaced the thermister probe (part number 471566) and the water temperature sensor (P/N 520272), which was reading 10ðF low. Neither of these items fixed the problem.

Any recommendations about what to troubleshoot next?

After troubleshooting this problem further with a Pentair technician, the control board was replaced. Now, the display only reads "OFF". There is no longer any cycling or water temperature reading. The green power light is on.

Any suggestions, please?