Bleb,
We have seen a number of reports of this problem...
I am not sure anyone knows for sure the cause. If your unit is under warranty I suggest you report it and have Pentair fix the problem.
If out of warranty, it is a pain, but since the cell is still working I'm not sure I would spend any money to fix it.
I had it happen to me once before and just turning the SWG off and then turning back on, solved the issue.. but this has not normally helped others.
It has been reported that replacing the Flow Switch assembly has made the problem go away, but I'm not sure if this is a fix or the cell just happened to work after the Flow switch was replaced.
Try to use this test and see what your thermistor (inside the flow switch) reads...
Pressing and holding the “More” button launches the System Status Mode. When the lights finish scrolling, the percent lights indicate hours of usage in 1,000s. For example, if the 40% light lights, that indicates 4,000 hours.
Version 3.1 on adds the ability to determine system temperature. Pressing the “More” button after the display shows 1,000s of hours of usage, will show temperature as follows:
Lights…………….....………Temperature
No LEDs………….…..………Below 30F
40%..........................36 to 45F
40% and 60%............46 to 55F
60%..........................56 to 65F
60% and 80%............66 to 75F
80%.........................76 to 85F
80 and 100%............86 to 95F
100%.......................96 to 99F
100% blinking……..….over 99F
All LEDs blinking……...Sensor bad
The temperature sensor is a 10k thermistor. Its resistance varies based on the temperature. The way it varies is known precisely. So the box measures resistance in ohms and calculates the temperature.
If the thermistor fails in a way that’s obvious to the software, the software will ignore the thermistor and use 75 degrees F as the temperature.
When using 75 as the default temperature, the salinity will be miscalculated by the software for any water temperature other than 75 F.
The further the water temperature is from 75F, the more error there will be in the salinity calculation.
If the thermistor drifts off calibration in a way that’s not obvious to the software, the software will use the incorrect temperature and the salinity will be off depending on how far the water temperature is from what the software thinks the temperature is.
I don't believe that cleaning the cell will fix this issue..
Thanks,
Jim R.