Ambient Thermistor, Blue

Rheem RTG20006UW Ambient Sensor – OEM Temperature Monitoring Component for Tankless Units

The Rheem RTG20006UW is an OEM ambient thermistor designed for use in select Rheem tankless gas water heaters. This sensor monitors the air temperature surrounding the unit, enabling the control system to optimize performance under varying environmental conditions. Ambient temperature input is used for system logic including combustion control, freeze protection, and operational safety checks.

Component Function

Installed within the water heater cabinet, this NTC thermistor delivers real-time ambient air temperature readings to the system’s main control board. Accurate ambient sensing is essential for proper burner modulation, particularly in outdoor or variable-temperature installations. The RTG20006UW helps prevent false ignition faults and supports system stability across a range of environmental operating conditions.

Technical Specifications

• Part Number: RTG20006UW
• Sensor Type: NTC thermistor (negative temperature coefficient)
• Application: Ambient air temperature monitoring for Rheem tankless gas water heaters
• Lead Termination: Plug-in connector to system control board
• Identification: Blue thermistor head (per OEM designation)
• Mounting: Internal chassis bracket or enclosure-mount (model-dependent)

Installation Requirements

Installation should be completed by a licensed technician. Disconnect power before servicing the unit. The thermistor should be secured in its designated bracket or mount, and the lead must be connected to the appropriate port on the control board without modification. Improper placement or loose connections may result in inaccurate readings or system faults. Verify installation with system diagnostics and confirm sensor response during startup.

Field Use and Replacement

Common indicators of thermistor failure include startup delay, error codes related to ambient temperature sensing, or inconsistent burner response in cold climates. The RTG20006UW is a critical component in maintaining proper system function and should be replaced with an exact OEM match to maintain diagnostic integrity and operational reliability.