Jandy TruClear Flow Issues: No Flow Display, Sensor Problems, and Plumbing

What "No Flow" Means

When the TruClear displays "No Flow," it has detected an absence of water flow during what should be a valid chlorination cycle. The system immediately turns off chlorine output to prevent dangerous gas buildup in a dry cell. This is a critical safety feature.

The flow sensor is located inside the cell housing. It detects the presence of moving water. Per the manual, this flow sensor is intended as a backup only — the primary protection is the electrical wiring that ties the power pack to the pump timer, ensuring the chlorinator cannot run unless the pump is on.

Step-by-Step Troubleshooting

Owner-Level Checks

1. Verify the pump is running

1. Confirm the pump is on, fully primed, and producing visible return flow at the pool jets.
2. If the pump is off, the TruClear should not be running at all (it is wired to the pump timer). A "No Flow" display while the pump is off may indicate a wiring issue.

2. Check and clean baskets

1. Empty the skimmer basket and pump strainer basket. Clogged baskets restrict flow below the 20 GPM minimum.
2. Check for debris in the pump impeller if baskets are clear but flow seems low.

3. Clean or backwash the filter

1. A dirty filter is the most common cause of reduced flow. Check the filter pressure gauge against your clean baseline.
2. Clean the cartridge, backwash the sand or DE filter, or replace filter media if it is beyond cleaning.

4. Check valve positions

1. Verify all suction and return valves are fully open.
2. If the system has a solar heater, water feature, or in-floor cleaner, confirm those diverter valves are not routing all flow away from the TruClear cell.

Tech-Level Checks

5. Check cell-to-power-pack connection

1. A poor or loose connection between the cell cable and the power pack can cause a false "No Flow" reading.
2. Unplug and reconnect the cell cable at the power pack. Ensure it is fully seated and secure.
3. Inspect the cable and connector for corrosion, damage, or moisture intrusion.

6. Verify cell installation orientation

1. The cell must be installed horizontally on pipe that runs within plus or minus 5 degrees of level. It cannot be mounted on vertical or sloping pipe.
2. The flow indicator arrows on the cell housing must match the direction of water flow. If installed backwards, the cell will malfunction.
3. The cable must exit the top of the cell, facing upward. This prevents flammable gas accumulation.
4. The cell should be on a pipe segment at least 16 inches long, installed as the last piece of equipment before the pool return.
5. The cell should be at least 10 inches from any 90-degree elbow to avoid turbulence-related flow detection issues.

7. Check pump sizing and speed

1. The TruClear requires a minimum of 20 GPM. On variable speed pumps at low RPM, you may not reach this threshold.
2. Program the pump to run at a speed that produces at least 20 GPM when the TruClear is expected to operate.
3. If the pump cannot produce 20 GPM at any speed, it may be undersized, have an impeller issue, or have significant plumbing restrictions.

8. Check for air in the system

1. Air trapped in the plumbing can cause intermittent "No Flow" events. Look for air bubbles at the return jets.
2. Check suction-side fittings, pump lid O-ring, and any unions for air leaks.
3. Open the air relief valve on the filter to bleed trapped air.

9. In-floor cleaning system check

If the pool has an in-floor cleaning system, the TruClear cell must be installed on a separate dedicated return line. Installing it on the in-floor system line can cause damage and intermittent flow issues as the valves cycle. If no dedicated return line exists, one must be plumbed.

Installation Requirements Summary

• Cell position: Last piece of equipment before the pool return, after heater, pump, and filter.
• Pipe orientation: Horizontal, within 5 degrees of level.
• Minimum pipe length: 16 inches.
• Distance from 90-degree elbow: At least 10 inches recommended.
• Cell cable: Must exit from the top, facing up.
• Flow arrows: Must match water flow direction. Incorrect orientation causes cell malfunction.
• Maximum distance from power pack: 15 feet (4.6 meters).
• Minimum flow rate: 20 GPM (76 LPM).
• Maximum operating pressure: 50 PSI.

How to Prevent Flow Issues

• Maintain clean filters. This is the single most common cause of reduced flow.
• Keep skimmer and pump baskets clean.
• Ensure variable speed pumps are programmed to deliver at least 20 GPM during chlorination periods.
• Fix air leaks promptly. Suction-side air leaks cause intermittent flow detection problems.
• Verify valve positions after any maintenance or winterizing work.
• If adding water features or in-floor cleaners, confirm the TruClear cell has adequate dedicated flow.