Thermistor Wiring Harness

RTG20319Y Thermistor Wiring Harness – Designed for Accurate Temperature Sensor Connectivity

The Rheem RTG20319Y is a factory-authorized thermistor wiring harness used in select Rheem tankless gas water heaters. This harness provides a dedicated connection path between the thermistors and the control board, enabling accurate temperature monitoring within the system’s heat exchanger and outlet. Its role is critical in maintaining consistent temperature modulation and protecting the unit against overheating or system errors.

Manufactured to original Rheem specifications, the RTG20319Y ensures a precise fit and proper function in compatible units. Designed for durability in high-temperature environments, this harness resists degradation over time, supporting long-term reliability in residential and light commercial applications.

Key Features and Functional Benefits

• Accurate Signal Transmission – Maintains integrity of thermistor readings for proper burner modulation and safety controls.
• OEM Fit and Finish – Specifically engineered for Rheem tankless systems to guarantee compatibility without modification.
• Heat-Resistant Construction – Rated for consistent operation in high-temperature water heater environments.
• Reduces Diagnostic Errors – A properly functioning harness helps prevent erroneous sensor readings and system lockouts.

Technical Specifications

• Part Number: RTG20319Y
• Application: Thermistor signal harness for temperature sensing circuits
• System Compatibility: Rheem tankless gas water heaters (refer to unit service documentation)
• Includes: Preassembled wiring harness (sensors not included)

Installation and Service Notes

Installation should be performed by licensed plumbing or HVAC professionals with experience in Rheem tankless systems. The unit should be powered off and safely isolated from gas supply prior to component replacement. Once installed, verify correct thermistor resistance values and check for fault codes on the controller. Improper connections can lead to control system failure or overheating risk.

Recommended For

• Service Technicians – Required during diagnostics when the existing harness shows signs of wear, damage, or intermittent connection issues.
• Scheduled Maintenance – Can be replaced as part of routine service when checking temperature sensors or control board terminals.