Repairing an IC40

[cleverscreenname]

I am brand new out here. just bought this house with an 25,000 gal in-ground pool. The Ic-40 worked for a little bit when i first fired up the pool, now nothing. It just sez low salt all the time, even though my salt is 5,900 ppm. I called pentair and there advice is to buy a new one. Can this be repaired? Any advice would help thanks!!

 

[jblizzle]

If the problem is with the cell, they can generally not be repaired.
Many pool stores have the ability to test whether the cell is good or not.

 

[mknauss]

What age is the IC40? They are notorious to have failed temperature sensors in the flow switch. Easy fix and if not under warranty you can get aftermarket brand switches for ~$60 on Amazon. Easy to replace.

If the unit is a new version, there is a protocol to check if the sensor is bad. It was posted on the forum so if you have a newer cell version we can search for it.

Take care.

 

[Jimrahbe]

csn,

Here is the test that was referenced above... it came from JamesW who is an expert on a ton of different stuff...


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 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.

 

[jblizzle]

Interesting, I did not consider that it could just be the sensor.

 

[cleverscreenname]

Thanks for all the information and help!! My ic40 is 5 years old. Do low temp. and low salt go hand in hand? Mine has the low salt problem.

 

[Philo]

Thanks for all the information and help!! My ic40 is 5 years old. Do low temp. and low salt go hand in hand? Mine has the low salt problem.

I think both are controlled from the sensor. My SWG was temperamental until I replaced the sensor, then smooth sailing!

 

[mknauss]

The result of a bad temperature sensor is a low salt indicator on the IC40. At 5 years old, it might be the cell is at the end of its life.

Can you do the System Status Mode process Jim shows to see how many hours your cell has run? If above 6000 or so -- might be time for a new cell.

Good luck.

 

[Philo]

I am brand new out here. just bought this house with an 25,000 gal in-ground pool. The Ic-40 worked for a little bit when i first fired up the pool, now nothing. It just sez low salt all the time, even though my salt is 5,900 ppm. I called pentair and there advice is to buy a new one. Can this be repaired? Any advice would help thanks!!

5,900 ppm for salt is VERY high. That will put a monkey wrench in it's ability to work as designed.

 

[mknauss]

5,900 ppm for salt is VERY high. That will put a monkey wrench in it's ability to work as designed.

Actually it will work fine at high salt concentrations. The issue is the high salt does get into the realm of corrosion of metal items in and near the pool when that high.

 

[Philo]

chem geeks thoughts:


"If the salt levels were very high, then the much higher currents might cause problems elsewhere in the system if not designed for such currents. Though they are for a shorter period of time, higher current through resistance means more heat generated and that can lead to higher temperatures, perhaps in the electronics, wires, etc. that might not be dissipated as effectively and could cause problems. I suspect you'd have to get the salt level pretty high before you see such effects".

Richard

 

[Akathisia]

chem geeks thoughts:


"If the salt levels were very high, ...I suspect you'd have to get the salt level pretty high before you see such effects".

Richard

How was the 5900 salt level obtained? Even so, is 5900 VERY high, PRETTY high or not really that high?

 

[jblizzle]

Pretty high for the US, normal for the Australian SWGs I think.

Ocean is 35000, so low compared to that

 

[JamesW]

Check for scale and clean if necessary.

 

[GinoDog]

csn,

Here is the test that was referenced above... it came from JamesW who is an expert on a ton of different stuff...


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 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.

Thank you, I followed your suggestions and I was able to find out the problem with “low salt” red light on on my ic40. Bad thermistor.