IntelliChlor Cell Not Working? You Might Only Need the Cell Circuit Board (Pentair 520724)
A dead IntelliChlor salt cell is one of the more painful surprises in pool ownership. A new cell can run close to two thousand dollars. But here's the part most pool owners never hear: there's a circuit board inside the cell itself, and when the lights go dark or the system stops seeing the cell, that board is often the real culprit. Pentair sells it separately as part 520724, and it costs a fraction of what a new cell does.
What does the circuit board inside an IntelliChlor cell do?
The board inside the cell runs the status lights, handles the sensor readings, and talks to the power center. The titanium plates only do one job, which is making chlorine. Everything "smart" about the cell happens on that board.
Your salt reading, the communication with your automation system, the lights that tell you output level, all of it routes through this one board. So when the board fails, the whole cell looks dead even if the plates still have plenty of life left in them.
Signs the cell board is bad (and not the plates)
The clearest sign is a cell with no status lights at all, or a "no communication" message at the power center, while the power center itself checks out fine. That points at the electronics in the cell, not the plates.
- No lights on the cell even though the power center is on and the pump is running
- Your EasyTouch, IntelliTouch, or IntelliCenter says it can't communicate with the chlorinator
- Salt readings that suddenly went haywire or disappeared, even though a water test shows your salt level is fine
- The cell stopped producing chlorine but the plates look clean and the cell isn't that old
One thing to rule out first: worn or scaled plates are a different problem with different symptoms. If your cell is five or more years old and output has been slowly dropping, the plates themselves are probably the issue, and a board won't fix that.
Is it the board, the power center, or the plates?
Work from the wall outward. Check the power center first, then the cell board, then the plates. That order saves you from replacing the wrong part.
- Power center first. Make sure the breaker is on and the power center shows signs of life. If the power center itself is dead, that's a separate repair (we've covered how to test the Pentair 520556 power center in another post).
- Then the cell. If the power center is fine but the cell shows nothing, the 520724 cell board is your prime suspect.
- Then the plates. If the lights work and the cell cycles normally but your chlorine keeps running low, test your water, confirm your salt level, and pull the cell to inspect the plates for scale buildup or wear.
Also check the obvious stuff before ordering anything. A tripped GFCI, low water flow, or a salt level that's actually low will all stop chlorine production without anything being broken.
How to replace the Pentair 520724 cell board
The short version: kill the power, remove the cell, open up the cord end where the electronics live, swap the board, and put it all back together. It's a manageable job for someone comfortable with basic tools.
- Turn off power to the chlorinator at the breaker. Don't skip this.
- Unscrew the cell from the plumbing and take it somewhere dry to work on.
- Open the housing on the cord end of the cell to expose the board.
- Take a photo of the connections before touching anything, then disconnect the old board.
- Install the new 520724 board, reconnect everything to match your photo, and reseal the housing carefully so no water gets in.
One important note: make sure the board matches your specific cell model before you order. If you're not sure, send us your cell's model and serial number and we'll confirm the right fit.
Repair or replace: when the 520724 makes sense
If your plates are in good shape and the cell is only a few years old, the board swap is the smart money. You're spending around $191 instead of close to $2,000 for a new cell.
If the cell is already near the end of its life, think twice. Most salt cells give you somewhere around five seasons, give or take, depending on run time and water chemistry. Putting a new board in a cell with worn plates just delays the bigger purchase without saving you much.
The bottom line on the Pentair 520724
A dark, silent IntelliChlor cell doesn't automatically mean the cell is toast. Rule out the power center and the simple stuff, and if the electronics in the cell are the problem, the Pentair 520724 circuit board can bring it back for a fraction of the replacement cost.
Pentair | 520724 | IntelliChlor Cell Printed Circuit Board Assembly Replacement
$190.99
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