Inlet Thermistor, White

Rheem RTG20006AR Inlet Thermistor – OEM Temperature Sensor for Tankless Water Heater Control

The Rheem RTG20006AR is a factory-authorized inlet thermistor designed for use with specific Rheem tankless water heater models. This sensor plays a critical role in system control by monitoring the temperature of incoming cold water and relaying accurate temperature data to the unit’s main control board for real-time burner modulation and flow adjustment.

Application and Function

This thermistor enables dynamic temperature regulation based on inlet conditions, allowing the water heater to adjust firing rates and deliver consistent outlet temperatures. Accurate inlet sensing is essential for proper flow regulation, freeze protection logic, and temperature stability across varying load conditions. The RTG20006AR is an OEM replacement part and should be installed in accordance with manufacturer guidelines.

Technical Specifications

• Part Number: RTG20006AR
• Component Type: NTC Thermistor (inlet water temperature sensor)
• Application: Rheem tankless water heater systems
• Connection Type: Factory plug-in wiring harness
• Mounting: Threaded or clipped insertion into cold water inlet manifold (model-dependent)
• Function: Measures incoming water temperature and transmits data to control board

Installation Requirements

System must be powered down and isolated from the water supply prior to service. Thermistor replacement involves disconnecting the electrical lead and removing the existing sensor from the inlet fitting. Thread sealant or O-rings (if included) must be inspected and replaced as required. Proper seating is critical to ensure sensor accuracy and avoid leaks. Installation should be performed by a licensed technician to ensure compliance with safety and performance standards.

Use in Field Applications

Common failure indicators include erratic outlet temperatures, error codes related to inlet water sensing, or burner cycling irregularities. The RTG20006AR is a frequently stocked part for service work involving control board diagnostics, temperature calibration issues, or preventive maintenance on tankless water heating systems operating in variable inlet conditions.