No Flow
Zodiac Pool System
Severity:What Does This Error Mean?
A Zodiac Jandy No Flow alert means the flow sensor in the heater or automation system detected that water is not circulating at the required rate. The most common causes are a clogged pump basket, a dirty filter causing high back-pressure, or the pump not running at sufficient speed. Check the pump basket and filter pressure before anything else.
Affected Models
- Jandy JXi Heater
- Jandy LXi Heater
- Jandy Pro Series Pool Heater
- Zodiac iAquaLink Automation
Common Causes
- Pump strainer basket is clogged with debris — restricting water intake
- Pool filter is dirty and needs backwashing — high filter pressure reduces flow
- Pump speed is set too low on a variable-speed pump
- Flow sensor is faulty or out of calibration
- Air in the system preventing prime
How to Fix It
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Check the pump strainer basket. Turn off the pump, open the basket lid, and remove any debris. A full basket is the most common cause of low flow.
Always turn off the pump before opening the basket to avoid injury and to allow the pressure to drop.
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Check the filter pressure gauge. If pressure is more than 8–10 PSI above the clean starting pressure, the filter needs backwashing or cleaning.
A clogged filter greatly reduces flow rate even if the pump is running normally. Backwash a sand or DE filter, or rinse a cartridge filter.
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If you have a variable-speed pump, check the speed setting. The Jandy heater requires a minimum flow rate — typically around 30 GPM. Increase the pump RPM if it is running at a low speed.
Jandy heaters will not fire below their minimum flow threshold and will display No Flow to protect the heat exchanger.
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Check for air in the system. Look at the pump strainer lid — you should see water, not air bubbles. Air in the pump indicates a suction-side leak or the water level in the pool is too low.
If the pool water level is below the skimmer opening, the pump pulls air instead of water. Add water to raise the level above the skimmer mouth.
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If all of the above check out and the No Flow alert persists, the flow sensor itself may be faulty. Contact a Jandy-certified pool technician to test and replace the sensor.
Frequently Asked Questions
Will the Jandy heater automatically retry after a No Flow fault clears?
Yes — once the flow sensor reads adequate flow, the Jandy heater will automatically clear the No Flow fault and attempt to fire. You do not need to manually reset it in most cases. If the fault keeps returning, the underlying flow problem has not been resolved.