Hayward Aqua Rite "No Flow" Light On: Causes and Fixes

What the "No Flow" Light Actually Means

The Aqua Rite uses a separate flow switch assembly that plugs into the control box. Inside the switch housing, a small paddle sits in the water stream. When water flows fast enough, it pushes the paddle to one side and closes an electrical contact. The control board reads that contact to know the pump is running.

If the paddle does not move, or the contact does not close, the board sees "no flow" and immediately stops chlorine production to protect the cell. The LED will flash briefly at startup (normal behavior while the pump gets up to speed), then go off once flow is confirmed. If it stays on solid or keeps flashing, the system believes there is a real flow problem.

Step-by-Step Troubleshooting

Owner-Level Checks

Confirm the pump is actually running

• Walk to the pump and verify it is on and making normal noise.
• Check that the timer or automation system has actually turned the pump on.
• If you have a variable-speed pump, make sure it is running at a speed high enough to satisfy the flow switch (usually at least medium speed).

Check filter pressure and cleanliness

• Look at the filter pressure gauge. If it is much higher than the "clean" baseline, the filter is restricting flow.
• Backwash a sand or DE filter, or clean a cartridge filter as needed.
• Recheck the "No Flow" light after restoring normal pressure.

Verify all valves are open

• Walk the plumbing from pump to returns and confirm every valve is in the correct position.
• Make sure any diverter valves for water features, solar, or cleaners are not blocking the main return path where the Aqua Rite and flow switch are installed.

Look for air in the system

• Air pockets can reduce effective flow and confuse the switch.
• Check the pump basket lid, union O-rings, and any valve stems for air leaks.
• Bleed air from the filter if needed.

Tech-Level Checks

Inspect flow switch plumbing layout

The manual is specific: the flow switch needs at least 12 inches of straight pipe before it (no elbows, tees, or valves in that zone) to get a clean, stable flow pattern. If it is installed right after an elbow or fitting, turbulence can prevent the paddle from reading correctly.

• Measure the straight run before the switch. If it is less than 12 inches, consider replumbing.
• Confirm the arrow on the switch body points in the direction of water flow. Installing it backwards will cause a constant "No Flow" fault.

Check the flow switch cable and connection

• Trace the cable from the switch to the control box. Make sure it is plugged in firmly and the connector is not corroded or damaged.
• Wiggle the cable gently while watching the "No Flow" LED. If the light flickers, you have a bad connection or damaged wire.

Test the flow switch mechanically

1. Turn off the pump and relieve pressure.
2. Remove the clear cap from the flow switch housing.
3. Look inside at the paddle. It should move freely on its hinge.
4. Turn the pump back on briefly and watch the paddle. It should swing to one side with the flow.
5. If the paddle is stuck, broken, or does not move, the switch needs replacement.

Test the flow switch electrically

• With the pump running and the paddle visibly pushed to the flow position, use a multimeter to check continuity across the two terminals in the switch.
• You should see a closed circuit (near zero ohms) when flow is present.
• If the paddle moves but there is no continuity, the internal contact is bad and the switch must be replaced.

Rule out control board issues

• If you have confirmed good flow, correct plumbing, and a working switch, but the "No Flow" light still will not go off, suspect the input circuit on the control board.
• Try jumpering the two flow switch terminals at the board (with the pump running) to simulate perfect flow. If the light still stays on, the board is likely at fault.

Common Parts That Fix This Problem

Flow Switch Assembly

Failed paddles, broken hinges, or corroded contacts inside the switch are common. Replacement switches are specific to Hayward salt systems.

Plumbing Modifications

Adding a longer straight pipe section or moving the switch away from elbows can solve chronic "No Flow" issues caused by turbulence.

Filter Cleaning or Replacement

If the filter is the restriction, service or replacement restores proper flow and clears the light.

Control PCB

Less common, but if the board's flow input circuit is damaged, replacement is required.

Model-Specific Notes

• The Aqua Rite flow switch is a simple on/off paddle type, not a pressure switch. It only cares about water movement, not PSI.
• Some installations use a "flow switch bypass" jumper for troubleshooting, but this is not a permanent fix and voids safety protections.

How To Prevent "No Flow" Problems

• Clean or backwash the filter regularly before pressure climbs too high.
• Install the flow switch in a location with at least 12 inches of straight pipe before it.
• Use a union or tee that makes the switch easy to remove for inspection without cutting pipe.
• Check the paddle and cable connection annually as part of routine maintenance.

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