Pool Chlorinator Not Working? Nine Checks to Make
A salt chlorinator can show power and still produce little or no chlorine. The fault may be water flow, salt level, cell condition, settings or the control unit itself. Check the simple causes before replacing parts.
Read the symptom before changing anything
| Symptom | Common possibilities |
|---|---|
| Low flow warning | Low water level, blocked baskets, dirty filter, closed valve, air leak or flow sensor fault. |
| Low salt warning | Salt is genuinely low, cold water affects the reading, the cell is scaled or the cell is ageing. |
| No chlorine result | Short run time, low output setting, high chlorine demand, poor water balance or no cell production. |
| Pump will not stop | Manual mode, an external controller, timer settings, relay fault or wiring configuration. |
Nine checks to make
1. Confirm water is moving
Look for a full pump basket and strong return flow. A chlorinator cannot operate correctly without steady circulation.
2. Empty the baskets
Turn the pump off, then clear the skimmer and pump baskets. A basket can look only partly full but still restrict flow when packed with fine leaves.
3. Check the filter pressure
Compare the gauge with the normal clean pressure for your system. High pressure may mean the filter needs cleaning or backwashing. Very low pressure can point to loss of prime or a suction restriction.
4. Check the actual salt level
Do not rely on the chlorinator display alone. Confirm the water with a suitable salt test or a professional water test. Adding salt without testing can create an unnecessarily high level.
5. Inspect the cell
With the power isolated, look for scale bridging the plates, debris inside the housing or visibly worn coating. Follow the manufacturer’s cell cleaning procedure. Repeated strong acid cleaning can shorten cell life.
6. Review output and run time
A low output percentage or short pump schedule may not meet demand during warm weather, heavy swimming or after rain. Output and filtration time should be considered together.
7. Check the clock and operating mode
Power interruptions can affect timers. Confirm the day, time, programmed periods and whether the unit is in automatic or manual mode.
8. Test the pool water
A working cell can still appear ineffective when chlorine demand is very high or water balance prevents chlorine from lasting. Test sanitiser, pH and the wider balance before blaming the cell.
9. Note the cell age and warning history
Cells are consumable parts. Intermittent low salt warnings, reduced production and frequent cleaning can indicate an ageing cell, especially when independent water tests show the salt level is correct.
Repair the cell or replace the chlorinator?
If the controller is sound and the correct replacement cell is available, a cell replacement may be sensible. If the control box, flow sensor and cell are all ageing, a complete system can offer better value. Compatibility with the existing plumbing, automation and pump must be checked before changing brands.
See our pool equipment range or learn about chlorinator repairs and upgrades.
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Pool Perfectionists provides practical troubleshooting, servicing and equipment advice across Sydney, with local technicians based in the Sutherland Shire.