Closing a Salt Pool? Why You Need a Pentair 520588 IntelliChlor Dummy Cell
Pool closing season sneaks up fast. If you run an IntelliChlor salt system, one of the smartest cheap things you can do before the water gets cold is pull the salt cell out and drop a Pentair 520588 dummy cell in its place.
It is a plain plastic pipe with the same union fittings as your cell. No plates, no wiring, no chlorine. It just keeps water flowing through the plumbing while the real cell sits safely in your garage.
What is a Pentair 520588 dummy cell?
The Pentair 520588 is a bypass cell that takes the place of your IntelliChlor salt cell in the return plumbing. It fills the gap so you do not have to cut pipe or build a temporary spool piece every time the cell comes out.
Think of it as a placeholder. Your plumbing stays sealed and your pump can run normally, but the expensive part is out of harm's way.
Why pull the salt cell out for winter at all?
Because a salt cell that freezes is usually a dead salt cell. The titanium plates inside sit close together, and trapped water expanding into ice can crack the housing or warp the plates. That is a several hundred dollar mistake for a part you were not even using.
There is a second reason people forget. Cells do not make chlorine well in cold water. Most IntelliChlor units cut output way back once water drops under about 60 degrees, so leaving it inline through winter buys you nothing anyway.
- Freeze damage to the cell housing and plates
- Scale building up on plates sitting in still water for months
- Cell body and cord exposed to ice, snow, and falling branches
- No usable chlorine output in cold water regardless
Can you just leave the salt cell in over winter?
You can, and plenty of people in warm states do. If your water never comes close to freezing and the pump keeps running, leaving it inline is fine. Rinse it, check it, move on.
Anywhere that actually freezes, take it out. The 520588 dummy cell costs a fraction of a replacement cell, and swapping it in takes about five minutes with no tools.
How to swap in the Pentair 520588 dummy cell
Do this after you have balanced and shocked the water, and before you drain the equipment lines.
- Shut the pump off at the breaker. Do not skip this.
- Unplug the cell cord from the IntelliChlor power center or automation panel.
- Loosen both union nuts on the salt cell by hand. They should not need a wrench.
- Lift the cell out and let it drain. Inspect the plates while you have it in your hands.
- Check both union o-rings. Replace any that look flat, cracked, or dried out.
- Set the 520588 in place, snug the union nuts by hand, and finish blowing out or draining the lines.
Store the real cell indoors, dry, standing upright, somewhere it will not get knocked over. A shelf in the garage is fine. A shed that gets down to 20 degrees is not.
Is the 520588 compatible with my IntelliChlor?
The 520588 uses the standard IntelliChlor union spacing, so it drops into the same spot as an IC15, IC20, IC40, or IC60 cell. If your plumbing was built for a Pentair IntelliChlor, the dummy cell fits.
Two things worth checking before you order. Make sure your unions really are the Pentair style and not an adapter someone plumbed in, and hang onto your existing union nuts and o-rings since the bypass cell body is what you are replacing, not the whole assembly.
The other time a bypass cell earns its keep
New plaster. After a resurface, the pool needs several weeks of careful startup chemistry with the salt system off, and running fresh plaster water through a salt cell is a good way to scale it up early. A 520588 lets you circulate and filter normally without exposing the cell.
Same story if your cell fails mid season and the replacement is on backorder. Drop the dummy cell in, run liquid chlorine for a couple weeks, and your pump and filter keep doing their job.
What it costs versus what it saves
A Pentair 520588 dummy cell runs about seventy dollars. A replacement IntelliChlor cell runs several hundred to over a thousand depending on the model. You do not need to be great at math to see how that trade works out if you close your pool every year.
It also lasts basically forever. There is nothing inside to wear out. Buy one, label it, and reuse it every fall.
Not sure this is the right part for your problem? Reach out and we will help you figure out exactly what you need before you spend money on the wrong thing.