Pentair IC40 weird lights


Bronze Supporter
Oct 13, 2016
It was installed as part of the original pool build in November 2018.

The salt level light flips rapidly back and forth between green and red
The flow light is red
The cell light is blank
The sanitizer level lights up 40%

When I do the self diagnostics, the 20% button lights up briefly and then turns off, showing that only 2000 hours on the cell have been used? That can't be right, because as I said this unit has been running almost continuously since November 2018.

The SWG is not producing any chlorine.

Chemical levels: Chlorine 4.0, pH 7.6, TA 70, CYA 50, CA 375, Salt 4000

Here is what I have done:

1. Verified that filter pressure is normal
2. Verified that water coming from pump to pool is normal flow
3. Verified normal salt level
4. Took out IC 40 unit and used camera to look for blockages in pipes leading to and away from SWG, verified no blockages
5. Inspected blades inside IC40, no residue visible
6. Used water hose to rinse out SWG
7. Acid washed SWG, verified that NO bubbles were forming when unit was flushed with acid
8. Replaced flow switch

Even after doing all this, the lights don't change.

I'm assuming the cell must be bad and need to be replaced. I'm just not sure why it shows only 2000 hours of use? When the cell goes bad, does that mean the self diagnostic test isn't valid any longer?


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

All those problem are because the cell thinks you have no water flow.. As long as the cell thinks that, it will not proceed past its initial tests.

Replacing the flow switch should have fixed the problem.. So, either the new flow switch is bad, or the connections are bad, or the cell is bad.

Or, you put the new switch in backwards, or your cell was is in backwards and someone reversed the Flow Switch to make it work...

Show us a pic of the cell installation so we can see the water flow.

I suggest that as a test only, you short the Red and Black wires coming from the cell, together. If the flow light does not turn green the cell has to be bad..

Here is a diagram for reference...


Jim R.


TFP Expert
Mar 2, 2011
Did you short the wires from the switch or from the cell?

Do you have a picture of the wiring that you did?

Do not run the cell with the flow switch shorted as it could potentially explode if the cell runs without flow.
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