SWG erroneously reading super high Salinity

[Bismarck]

I have a Pentair IC40 SWG. I've used strips and the had the water tested and I know that the true salinity is about 2900ppm. My SWG has shut off as it was reporting 4200 ppm. It was giving me a flashing green salt light ( salt level high). This wouldn't be an issue as I just know that it is incorrect, except that it will not produce any chlorine when salinity is above 4000ppm from my understanding. I did a 1 part acid/ 3 part water wash on the cell to try to correct this, and it actually got worse and now is reading 5000ppm. Does anyone know how salinity is measured by these devices? I've looked for a way to calibrate them but not found anything online other than for the older version. I should mention that when I just got started with the pool I didn't know what I was doing and acid washed the cell with straight acid for about 15 minutes. I'm guessing that has finally come back to bite me? Is there a way for me to bypass or trick or otherwise circumvent its self protection? It is worthless if it will not produce chlorine for me, so I'm not averse to tinkering with it etc..... I have replaced the flow sensor last year and I know that changed my salinity level so I'm guessing it plays a part in the determining of salinity somehow?

Help!

Charles

 

[mas985]

Do you have solar and when solar engages, is that when the unit reads high salt?

Does anyone know how salinity is measured by these devices?

The unit measures voltage, amps and water temperature although I don't think the IC40 uses water temperature which is why I asked the question above. These values are then used to calculate the salt value which is related to all three. But there have been reports of the IC40 drift with temperature which makes me believe that it does not use temperature for the calculation. So when hot water hits the cell, it reads higher salt. If they corrected for that, then it wouldn't.

 

[pooldv]

The IC40 should not report high salinity until 4500 ppm. It will give high salt error but, it will continue to produce chlorine. It does not have a low temp indicator, mine gives a low salt error when the temp is low. Sounds like yours is about done.

 

[JamesW]

The IC40 has a conductivity sensor inside the cell. It does not have a temperature sensor. (Edit- it does have a temperature sensor. See update below).

I don't think that it uses the cell performance in calculating the salinity, but it might.

 

[MARCO...polo]

Snipped from the Pentair ICxx manual:

"Salt Level Status LEDs
The IECG salt level checks the pool water daily and displays the levels as follows:
Green LED:
Good salt.
The pool water salt level is between 2800 ppm
and 4500, and the IECG is producing chlorine. IECG salt LED should
always be showing GREEN level for better results.
Green LED (Flashing):
Salt level is above 4500 ppm. Chlorine is being
produced but the salt level is too high which increases the risk of
corrosion and deterioration of pool equipment and surfaces in and around
the pool. Pool water needs to be drained and refilled one (1) foot at a
time until the salt level is below 4500 ppm."

AND


"The salt sensor reading is within +/- 500 ppm accuracy"

With a possible +/- 500ppm variance on an amount of 4000 I'm not sure the word accuracy should even be in the sentence. I use a K1766 test kit and on occasion strips and rely solely on those numbers.

 

[pooldv]

Most salt tests are +/-400 ppm.

 

[JamesW]

Update: The IntelliChlor uses the Harwil Q-12DST-C2, which detects flow and temperature. It has an integrated 10k thermistor. There are four wires, red, black, green and white. Red and black go to the flow switch. Green and white go to the thermistor. I'm assuming that the salinity is temperature compensated.

 

[mas985]

Based upon previous posts that show wide salinity changes with temperature, the IC40 doesn't appear to be temperature compensated. Unless Pentair made changes to the newer versions.

 

[JamesW]

If they're using a temperature sensor, I would assume that they would incorporate the temperature into the salinity measurement. I'm not sure what else they would do with the temperature. Maybe just to make sure that the temperature is within limits?

Probably need to check with Pentair for the answer.

To the OP: What flow sensor did you use? Did it have the four wires, or just two? Perhaps getting a new flow sensor would help.

http://www.pentairpool.com/pdfs/ntellichloFlowSwitchReplacementKitIG.pdf