Pentair 42002-0024S Stack Flue Sensor

Part # 42002-0024S — the replacement stack/flue temperature sensor designed for use in select Pentair and Sta-Rite pool/spa gas heaters. This sensor monitors flue-gas temperature to ensure safe and proper combustion performance.

Key Features

• Designed specifically for gas-fired pool and spa heaters requiring a stack/flue sensor.
• Detects excessive flue-gas temperature or blocked flue conditions and signals the control system accordingly.
• OEM part that assures compatibility and reliability with the original heater model’s control electronics.
• Compact threaded design for drop-in replacement of the original sensor in the flue pipe or exhaust stack.
• Essential for avoiding error codes related to flue sensor faults and maintaining heater safety compliance.

Typical Applications

This sensor is used when the heater displays stack/flue sensor fault codes (such as E05 or E06) or when the original sensor has failed, corroded, or is out of spec. It is commonly installed in Pentair and Sta-Rite gas heaters to restore safe operation and proper exhaust monitoring.

Installation & Compatibility Notes

Before installing, turn off electrical power and gas supply to the heater and allow it to cool. Remove the heater flue cover or access panel, locate the existing stack/flue sensor, disconnect wiring, and unthread the old sensor. Thread in the new 42002-0024S sensor snugly (do not overtighten), reconnect the wiring in the same orientation, restore power and gas, and restart the unit. Monitor the heater through a full start-up to verify normal operation and no fault codes are present.

Why Choose This Sensor?

Selecting the correct OEM sensor like the 42002-0024S provides confidence in fitment, performance and heater safety. Generic or mismatched sensors may result in improper readings, recurrence of fault codes, or reduced heater lifespan. For pool professionals and service techs, this part ensures the heater operates within its designed limits.

Maintenance Tips

• Inspect the sensor and its mounting area annually for corrosion, soot accumulation or thermal damage.
• Check wiring connections for secure fit, insulation damage, or discoloration—loose or damaged wires often cause fault codes.
• Ensure the flue/exhaust piping is clear of obstructions or corrosion—sensor faults may be caused by blocked or damaged exhaust flow.
• When replacing the sensor as part of heater service, consider logging the heater runtime and verifying the flue-gas temperature is within specifications post-service.