AquaRite S3 Flow Problems: Pump Running but No Generation

What "No Flow" Actually Means

The AquaRite S3 uses a flow switch installed in the plumbing after the filter to detect when water is moving through the TurboCell. This is a safety feature—generating chlorine without flow can overheat the cell, create dangerously high localized chlorine concentrations, and damage the titanium plates. When the S3 doesn't see a closed flow switch signal, it refuses to generate regardless of all other settings.

The flow switch is a simple mechanical device: water flow pushes a paddle or piston that closes an electrical contact. When flow stops or drops below the activation threshold (typically 10-15 GPM depending on switch model), the paddle falls back and the contact opens. The S3 monitors this contact continuously and will shut down generation within seconds of losing the flow signal.

A "no flow" condition can be real (water isn't actually flowing through the cell), or false (water is flowing but the switch isn't detecting it due to installation errors, mechanical failure, or wiring issues).

Step-by-Step Troubleshooting

Owner-Level Checks

1. Confirm the pump is actually running

• Walk to the pump and verify it's energized and spinning.
• Check that returns are pushing water into the pool—a running pump with closed valves or a clogged impeller can appear to run but move very little water.
• If the S3 controls the pump via RS-485 or Smart Relay, verify the current time falls within an active pump schedule and that the schedule is set to run mode (not spa, backwash, or off).

2. Check valve positions

• Walk the plumbing and confirm all valves are set to allow flow through the salt cell.
• Common mistakes: spa mode diverting water away from the pool return line, solar bypass valves closed, or three-way valves positioned for backwashing or winterization.
• If you have a valve automation system (Hayward Omni, Pentair IntelliCenter, etc.), verify the valve actuators are actually in the positions the controller thinks they are.

3. Check filter pressure

• A dirty or clogged filter dramatically reduces flow rate, even with the pump running.
• Compare current pressure to the clean baseline pressure noted on the filter tank or in service records.
• If pressure is 8-10 PSI above baseline, clean or backwash the filter and observe if flow returns.

4. Verify pump speed setting

• If you have a variable speed pump, check what RPM it's running at during the period when the S3 should be generating.
• Very low speeds (below 1500-2000 RPM depending on plumbing) may not produce enough flow to activate the switch.
• If the S3 is controlling the pump, verify the chlorination schedule is set to run at a speed high enough to meet the flow switch threshold.

Tech-Level Checks

5. Inspect flow switch installation and orientation

• Locate the flow switch in the plumbing—it should be installed vertically (flow upward) after the filter and heater but before the cell.
• If the switch is horizontal or inverted, the paddle may not close properly even with good flow. Correct orientation is critical.
• Check that the switch is the correct model for your pipe size. A 2-inch switch in 1.5-inch pipe or vice versa may not activate reliably.
• Ensure the arrow on the switch body points in the direction of flow. Installing backwards can prevent activation.

6. Test the flow switch electrically

• With the pump running, disconnect the flow switch wires at the S3 control board or at the switch itself.
• Use a multimeter set to continuity mode to test across the two flow switch terminals.
• With flow, the switch should show continuity (closed circuit). Without flow, it should show no continuity (open circuit).
• If the switch doesn't close with confirmed flow, it's mechanically stuck or failed and needs replacement.
• If it does close, the problem is likely wiring between the switch and the S3 board.

7. Check flow switch wiring

• Trace the wires from the flow switch to the S3 control terminals.
• Look for damaged insulation, pinched wires, corroded connections, or loose terminals.
• Measure continuity from the S3 terminal block to the flow switch with the wires disconnected at the switch end. Each wire should show near-zero resistance.
• If you find an open or high-resistance wire, replace or repair the run.

8. Measure actual flow rate at the cell

• If possible, install a temporary flow meter or observe the pressure drop across the cell to estimate flow rate.
• Most residential salt cells need at least 10-15 GPM to activate the flow switch reliably.
• Undersized pumps, long plumbing runs, excessive fittings, or multiple restrictive devices (in-line chlorinators, UV systems, etc.) can all reduce flow below the threshold even with a properly sized pump.
• If flow is genuinely low, you'll need to address the hydraulic problem—clean the filter, reduce restrictions, or increase pump speed.

9. Test for schedule and control logic issues

• If the S3 is controlling the pump, print or write down all pump and chlorination schedules.
• Verify they overlap correctly—the S3 can't generate if the pump schedule turns off before the chlorination schedule runs.
• Check for mode conflicts: if the system is set to spa mode or a cleaning mode, flow may be diverted away from the cell even though the pump is running.
• Some S3 installations have external interlocks (freeze sensors, remote switches, etc.) that can disable the flow switch signal. Trace all control wiring to identify any unexpected interruptions.

Common Parts That Fix This Problem

Flow Switch Replacement

Flow switches fail over time due to scale buildup, paddle breakage, or worn contacts. Replacing the switch is straightforward and restores reliable flow detection. Common Hayward part numbers: GLX-FLO-RP (1.5-2 inch) or similar depending on plumbing size.

Flow Switch Relocation or Reorientation

If the switch is installed incorrectly (horizontal, inverted, or in turbulent flow), moving it to the proper vertical position after the filter often solves chronic no-flow issues without needing a new switch.

Filter Cleaning or Replacement

A clogged cartridge, dirty DE grids, or exhausted sand can choke flow to the point the switch never activates. Cleaning or replacing filter media restores flow and allows the S3 to generate normally.

Pump Speed Adjustment or Upgrade

If your variable speed pump runs too slowly to meet the flow switch threshold, reprogramming the speed schedule or upgrading to a higher-flow model may be required. This is more common on very large pools or complex plumbing with multiple water features.

Model-Specific Notes

• The S3 series uses standard Hayward flow switches compatible with older AquaRite and AquaLogic systems, so replacement parts and installation methods are the same.
• If your S3 is integrated with an Omni or ProLogic automation system, flow detection may also depend on valve position feedback. Check that the automation controller agrees with physical valve positions.
• Some S3 installations use a flow sensor rather than a mechanical switch (pressure transducer or electronic flow meter). Troubleshooting these requires different techniques—consult the specific sensor documentation.

How To Prevent Flow Switch Problems

• Install the flow switch vertically (flow upward) in a straight section of pipe with at least 6 inches of clearance on both sides to ensure laminar flow.
• Clean or backwash the filter regularly to maintain adequate flow rate and prevent pressure buildup.
• Set variable speed pump schedules to run at sufficient RPM during chlorination periods. A good rule of thumb: aim for at least 20-30 GPM during generation.
• Inspect the flow switch paddle annually for scale or debris buildup and clean as needed.
• Avoid installing additional restrictive devices (UV, ozone, etc.) downstream of the flow switch without verifying flow rate remains adequate.

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