I have a 2001 Sundance Cameo running on 240V with a Sentry 850 controller with a data code on the board of Nov 6, 2001, part number 6600-056 Rev C. Last year it developed a problem with FLO. The LCD said FLO (steady, not flashing) and panel locked up. If I cycled the breaker I could operate the jets and heater controls before the FLO error sets. If I turned the heater up to where it turns on the circulation pump operates fine, however when the temp is reached the heater turns off and the circ pump runs for a couple minutes and then turns off and FLO error came up. I verified that the control relay for the circ pump on the PCB is switching off and checked that power is not being directed to the circ pump when off and is applied when relay is on. I was able to play with the clock and circ turn on time to "fake" the controller out. This worked because it now saw flo. After a week of "normal" operation the water temp was at 114 and OH displayed and panel locked up. I shut the tub down for the year and forgot about it. This year I started up the tub and all was fine for two weeks and then we had a power outage. Then the same as last year with the fake out and water temp too high.

I have changed the filter to try the easy stuff. I believe that the controller is confused. If I knew how to reset it I would try that.

Does anyone have any suggestions on how to further diagnose the problem? - Thanks!

Replace the temperature sensor. Common problem.

May also be time to replace the circ pump or pull it and clean it out thoroughly.

Thanks for your quick reply. I want to make sure I did not confuse anyone - or even myself for that matter - so let me verify your recommendations.

You recommend replacing the temperature sensor even though the LCD reads 114 and my external thermometer agrees with this reading. This tells me that the sensor is reading properly, and the circuit board is presenting the temperature properly, but the circuit board forgot to turn off the heating circuit.

You also feel the circ pump is bad or needs cleaning even though it turns on when the circuit board relay is closed and turns off when the relay opens. I guess I can see this if the pump was putting excessive electrical stress on the circuitry.

Thanks for your patience and help while I get my thoughts straight.

Yes - it's your only option at this point short of replacing a $500 circuit board.

That circ pump is under continuous use and is highly subject to clogs and build up.

More clog/build up actually means LESS current draw. Electrical 'stress' will have nothing to do with it.

Thanks for the information Pageup. The stress I was talking about would be more of a resistive load on the circuitry due to an electrical malfunction of the pump. But I am an electrical guy so that is of course where I would go. I hadn't thought of buildup in the pump.

The more I read other posts you have made about this circulation pump and about how it is used all the time and can get clogged has me wanting to go this route first. Today I will figure how to take it out and inspect it well. I will post after my findings.

Thanks again!