Hot Water Thermistor With O-Ring

Rheem RTG20329M Hot Water Thermistor with O-Ring – OEM Sensor for Tankless Units

The Rheem RTG20329M is a factory replacement hot water outlet thermistor designed for use in Rheem tankless gas water heaters. This thermistor is critical for monitoring the outlet water temperature and ensuring accurate temperature regulation via the unit’s onboard control system.

The sensor comes equipped with a sealing O-ring to maintain watertight integrity at the installation point. When used in compatible models, the RTG20329M helps maintain system performance, prevents temperature fluctuation, and supports error code resolution related to water temperature sensors.

Application and Technical Details

• Part Number: RTG20329M
• Function: Hot water outlet temperature sensing
• Sensor Type: NTC thermistor
• Mounting Location: Factory-designated sensor port on hot water outlet pipe
• Includes: Thermistor assembly and O-ring seal
• System Type: Rheem tankless natural gas and propane units (model-specific compatibility required)

Installation Guidelines

Installation requires system shutdown and water line isolation. The thermistor installs directly into the designated outlet port on the tankless heat exchanger using the included O-ring. Ensure sensor cable routing does not interfere with combustion components. Do not reuse a deformed or degraded O-ring, and avoid overtightening to prevent cracking or stress on the heat exchanger boss.

While installation is relatively straightforward for experienced technicians, it is essential to verify proper resistance readings post-installation to confirm sensor functionality. This sensor does not require calibration if installed on a supported model.

Field Service Considerations

• Use as a direct replacement when outlet temperature error codes are detected (typically error codes 11, 61, or P1 depending on model firmware).
• Should be tested with a multimeter for proper resistance range based on water temperature prior to installation.
• Replacement intervals vary; inspect condition during scheduled maintenance of tankless units.
• Do not substitute with non-OEM thermistors as accuracy and communication with the control board may be compromised.

Designed for Professional Use

The RTG20329M is intended for licensed professionals servicing or maintaining Rheem tankless gas-fired water heaters. This part plays a critical role in system control and safety, ensuring that the heater delivers water at the set temperature without overheating or system error.