Hayward CAT Controller ORP Sensor Probe 10 Foot Cable

Hayward CAT Controller ORP Sensor Probe, 10-foot cable (W3PRO25-10). OEM replacement ORP electrode for Hayward CAT and HCC series chemical automation pool controls. 1/2" NPT ABS body, BNC connector. 2-year warranty. For installations where the controller and flow cell are farther apart than the 24-inch version can reach.

• SKU: W3PRO25-10
• 2-year warranty
• 10-foot cable for equipment rooms where the controller and flow cell are not adjacent
• Compatible with CAT1000, CAT3500, CAT4000, CAT5000, CAT5500, HCC1000, HCC2000
• Direct replacement; same BNC connector and port threading as factory-installed probe
• 1/2" NPT injection-molded ABS body
• Verify against a calibrated portable ORP meter after installation; agreement within 10 to 20 mV is acceptable
• ORP setpoint target: 650 mV or above per CDC Model Aquatic Health Code
• Recommended replacement interval: every 12 to 24 months
• Need a gold tip for demanding environments? See W3PRO25-AU-10

Hayward CAT Controller ORP Probe (W3PRO25-10): ORP Monitoring for Commercial Pool Chemical Automation

ORP (oxidation-reduction potential) is the millivolt signal the CAT controller uses to trigger chlorine dosing. Without an accurate ORP reading, the controller has no reliable basis for sanitizer management. The W3PRO25-10 restores that measurement link with a direct-fit 10-foot cable suited to installations where the flow cell and controller are not side by side. Install in a flow cell or bypass sample cell on the pool return line, downstream of filtration and chemical injection, for representative continuous readings. No adapters or controller reconfiguration required.

ORP vs. pH: Why Both Probes Matter

ORP measures oxidizing capacity; pH determines what fraction of that chlorine is active hypochlorous acid. At pH 7.8, the same chlorine concentration produces meaningfully lower ORP than at pH 7.4. The CAT controller monitors both simultaneously for coordinated acid and chlorine dosing. Replace both probes at the same service interval for the cleanest result.

Hayward CAT ORP Probe 10-Foot Specifications

Frequently Asked Questions

How is ORP probe verification different from pH calibration?

pH probes use two-point buffer calibration (pH 7.0 and 4.0). ORP probes are verified by comparing the controller's millivolt reading against a portable ORP meter from the same water sample. If the two agree within 10 to 20 mV, the probe is functioning correctly. A large or unstable discrepancy indicates a fouled or depleted probe.

My CAT controller shows stable ORP but my DPD test shows low chlorine. What does that mean?

A stable but fixed millivolt reading that doesn't track with known chlorine changes is the classic sign of a fouled or depleted probe that has stopped responding to actual water chemistry. Verify against a portable ORP meter and replace if it fails to agree within tolerance.

When should I use the gold tip version instead?

The gold tip (W3PRO25-AU-10) is better suited to indoor pools, therapy pools, and high-bather-load facilities where elevated combined chlorine is a recurring issue. For standard outdoor commercial pools with well-balanced chemistry, the standard platinum version is appropriate.