pentair minimax nt tsi w/ddtc won't start

JMarkoJuly 4, 2014

My Minimax NT TSI w/DDTC does not start. The green power button is lit up on the DDTC but the display only shows "OFF". No error code is shown, but the heater never starts. Is it possible that the thermister probe (part number 471566) is bad ? But if so, shouldn't there be some error code?

If I turn off completely, the screen reads 888. When I turn it back on, the Power LED illuminates and the screen reads OFF. No matter if I use Pool Mode, Spa Mode, or Remote Mode, the heater never starts.

Any suggestions?

This post was edited by JMarko on Fri, Jul 4, 14 at 20:28

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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.

    Bookmark   July 6, 2014 at 3:15PM
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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?

    Bookmark   July 26, 2014 at 12:59PM
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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?

    Bookmark   September 14, 2014 at 1:47PM
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