Pentair IC40 Red Flow light after replacement


New member
Jun 9, 2020
Hi everyone,

I just finished installing a new flow switch on my Pentair Intellichlor IC40 because the flow light was off and I noticed the flow switch was cracked and my pool was starting to turn green. After installing the new flow switch, the Flow light is now red and the high salt and low salt lights are flickering back and forth. I’m yet to test the levels because I recently had a lot of chlorine, acid and other chemicals added by a pool guy to remove the green that was starting to form.

Any guidance would be appreciated.

Thank you


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

If your pool was green, then most likely your red flow light is due to low flow through the cell.. This is because your filter is plugged with algae...

The first thing you should do is feel the flow of the water going back to the pool.. It should be good and strong.. If it is strong then the filter is ok and it has to be something else.

Tell us how strong the return water feels and what your filter pressure is..

What type of pump do you have? If a Variable speed pump, tell us what RPM it is running..

Please fill out your pool's signature so we all know what type of pool and equipment you have. It will save us from asking a lot of questions.. Just go to Setting and then Signature. You can use mine as an example.


Jim R.
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