Pentair Intellichlor salt levels jump from 0 to 4000

[StagsCliff]

My Intellichlor IC60 salt levels started bouncing around about 2 weeks ago, from 4300 to 0 to 3900 to 0 to 600 and now back to 4300 (yup it's a bit high, but the rain from Dorian should resolve that). I've confirmed salt levels ~4000 with test strips. chem test and a salt meter.

The cell is clean, and lifespan usage is under 20% (1 LED). I replaced the flow/temp sensor last year, and the flow sensor seems OK.

Pentair support says "The electronics are the first thing to go." But I'm not really keen on replacing the entire SWG when it has 80% life left.

Does anyone know whether its the SWG plates or the temp/flow sensor that does the salinity measurement? Because if it's the temp/flow sensor that does it - or maybe the temp sensor is going bad - then that's a lot easier to replace than the whole thing. Unfortunately the Intellichlor temp reading isn't shown by the Intellitouch control system (even though it's transmitted as an Intellichem would show it), so there's no easy way to see if the temp sensor is the culprit.

 

[ajw22]

The IntelliChlor uses a conductivity sensor inside the cell to measure salinity. The sensor reading is adjusted using the temperature from the flow switch.

Does it throw the LOW SALT light? If the cell continues to generate I would ignore it.

 

[Jimrahbe]

SC,

Here is a test you can run provided by JamesW...

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

Hold down the MORE button on cell for 6sec and watch the Cold Water/PWR light if it goes RED that tells you the temp sensor is bad and you need to swap out the flow switch/temp sensor (520736). If it doesn’t turn RED it could still be bad but it just hasn’t failed completely and then you need to make sure salt level in the pool is 3500 or above if it is swap flow switch/temp sensor (520736)

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 suspect that the software is probably getting a temperature reading in the high 80s or 90s.

One thing you could do is to cut the green and white wires. This should make the software use 75 F as the default temperature since it will lose contact with the sensor. This might make the cell work again.

You could measure the resistance of the sensor by putting the test leads on the green and white wires going to the sensor. The resistance should match a 10k thermistor chart. For example.

Temperature……….Ohms
60……………………… 15,310
70……………………… 11,882
77…………………….. 10,000 (The 10K reference point)
80…………………….… 9,297
90......................7,333

For example, if you measure the resistance as 7,333 ohms, the system thinks the temperature is 90F.

However, if the water is only 65 F, then the system is going to calculate the salinity as much lower than actual.

Thanks,

Jim R.