Rheem sp11798b High Limit Thermostat

Product Description

The RHEEM sp11798b is a high limit thermostat designed to protect heating systems from unsafe operating temperatures. When supply-air or heat-exchanger temperatures exceed a set threshold, the high limit interrupts the control circuit and shuts down the burner or heating element, preventing equipment damage and reducing safety risks. Licensed HVAC technicians install this component as part of routine service or when diagnosing nuisance shutdowns and overheating faults in residential or light-commercial heating systems.

High limit thermostats are a standard safety control in gas furnaces, electric furnaces, and hydronic heating equipment. The sp11798b is suited for replacement applications where the original high limit has failed open, failed closed, or is tripping at incorrect temperatures. Installation typically occurs on the heat exchanger plenum, supply-air duct collar, or burner compartment, depending on the equipment design.

Key Features

• Interrupts the control circuit on high-temperature events to protect the heat exchanger and downstream components
• OEM-style replacement designed to restore factory safety performance
• Compact form factor suited for direct swap in existing mounting location
• Compatible with standard low-voltage control circuits common in residential heating systems

Compatibility

Designed as an OEM-style replacement high limit thermostat for RHEEM heating systems. Consult the equipment service manual and verify the part number against the unit nameplate before ordering to confirm fitment.

Installation Notes

A licensed HVAC technician should perform this replacement. Shut off all power to the unit at the disconnect and, for gas appliances, close the gas supply valve before beginning work. The high limit must be mounted securely in the OEM location and wired into the low-voltage control circuit per the equipment wiring diagram. After installation, verify proper system operation through a complete heating cycle and confirm the limit does not trip under normal operating conditions before returning the equipment to service.