Pentair Flashing Green Cell Light


Jun 21, 2015
Leawood, KS
Hi all, I've read several threads on this topic and haven't been able to find a solution to the issue I'm having here.

I came home from travel last week and the pool had a tinge of green to it. I found a flashing green cell light on the Pentair Intellichlor and it appears to not be producing. Water balance is fine per my own tests and the pool store guys found the same (other than chlorine lower than I'd like). I have CL tabs in the pool now while I try to figure this out and hopefully get the cell producing again.

Here's the details on the pool
  • I have a ~ 27K gallon gunite pool
  • This is my 7th year of owning the pool. My guess is it is 20+ years old.
  • The system has a single Pentair IC60 SWG with 60% life used
  • I also have a spare cell (IC40) with 40% life used (Yes, I have's a dumb story)
  • Water balance is 2 CL, 70 CYA, 200 Calc Hardness, 7.5PH, Salt 3800 (pool store) - 4000 (my test)
Both cells are behaving exactly the same....they power on, test the salt level, then produce CL for about 3-5 mins before stopping CL production and flashing the Green Cell light. I've tested both cells in the plumbing. I've also had them both out and filled with pool water, powering them up and then holding the flow switch. Both produce CL and then cease CL production (flashing Green Cell light) after 3-5 minutes.

Actions I've done so far
  • I acid cleaned both cells twice yesterday
  • The IC 60 was showing a bad temp sensor in the "More" test, so I replaced the flow/temp switch earlier today. The temperature test is now reading correctly (same as the IC40), but the cell is still acting as described above
  • The IC 60 is now back installed and continues to exhibit the symptoms and patterns described above
I'm scratching my head here, perplexed that two different cells are exhibiting the same failure and symptoms. Looking for common variables now, I'm down to considering the water chemistry, the power supply or two bad cells.

Other than having to replace the glass fuze in the power supply earlier this season, it's been a solid performer. Is there something in the water I should be testing for that would cause the cells to stop producing CL? I really do not want to buy another Pentair Intellichlor right now, the prices look like they've doubled since I last purchased in 2018.

Thoughts? Thanks for taking a look.



Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
Bedford, TX

If the Cell light is flashing, when the cell is clean, then I have yet to see one where the cell was not dead.

I have three saltwater pools and all three had the same identical Cell light flashing failure mode. One lasted almost 9 years, one about 7 years and the last one that I just replaced today lasted a little over 5 years.

You can often get a few extra weeks out of them if you run your salt at the upper end of the range.

In my opinion, the "life used" test is more of a wild guess than an actual test. And, in the big picture it makes no difference... Either the cell works or is does not work, no matter what the life used test shows. The more often you acid wash the cell, the more of its life you use up.


Jim R.
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