Low NOX Blower Vacuum Switch

Rheem SP20117 – OEM Blower Vacuum Switch for Low NOX Water Heaters

The Rheem SP20117 is a factory-authorized replacement blower vacuum switch engineered for use in select Rheem, Ruud, and Richmond low-NOX gas water heater models. This switch is an integral part of the water heater’s induced draft system, serving as a safety control that verifies proper airflow before burner ignition.

Designed to ensure that combustion only occurs under safe operating conditions, the SP20117 closes the electrical circuit once sufficient negative pressure from the draft inducer is detected. If venting is obstructed or airflow fails to meet specifications, the switch prevents burner activation, mitigating risk to equipment and occupants.

Key Functions

• Airflow Verification: Confirms inducer fan operation and unobstructed venting before ignition is permitted.
• Safety Control: Prevents burner activation in the event of inadequate draft, maintaining safe combustion conditions.
• Low NOX System Integration: Designed specifically for use with Rheem's low-NOX compliant water heaters.
• System Interlock: Functions as a normally open switch that closes under vacuum pressure, completing the ignition circuit.

Technical Specifications

• Part Number: SP20117
• Application: Draft-inducing blower safety control
• System Type: Low NOX FVIR gas water heaters
• Switch Type: Vacuum-actuated pressure switch, single-pole
• Electrical Connection: 2-pin connector with mounting bracket
• Mounting: Pre-installed bracket for chamber mounting

Compatible Models

• Designed for use in Rheem and Ruud Low NOX FVIR gas water heaters equipped with induced draft blower assemblies
• Check model and serial number to confirm compatibility before ordering

Installation Overview

Installation of the SP20117 should be performed by qualified personnel familiar with combustion safety devices and FVIR gas systems. The switch must be properly aligned and connected to the blower assembly tubing to accurately detect pressure differentials. Electrical terminals must be securely connected to the ignition control board, and the system should be tested for proper draft detection before restoring operation.

Contractor Considerations

• Direct-fit replacement ensures minimal system downtime
• Essential control for maintaining combustion safety compliance
• Stocked frequently as part of routine service kits for induced-draft FVIR units

Important Notes

• This switch is pressure-specific; do not substitute across non-equivalent models
• Always test for proper blower function and flue clearance when replacing the vacuum switch
• Failure to install correctly may result in ignition lockout or unsafe operating conditions