If your system requires an external equalizer

Enhanced System Safety: Actively monitors high-side discharge pressure to prevent catastrophic hardware damage during restricted airflow or fan motor failure

which is critical in applications where a damper must remain partially open to ensure a minimum percentage of air circulation even when the controller signal is at zero

keep runs short and limit total wiring resistance to under 2 ohms to maintain calibration

Compatibility depends on your unit's model and serial number

Lochinvar & A.O. Smith 100233698 Gasket R-407A If your system requires anThe Lochinvar & A. O. Smith 100233698 Gasket is a critical OEM replacement part engineered for high efficiency condensing boilers and commercial water heaters. This venturi gasket serves as the primary sealing interface between the blower fan and the venturi assembly, ensuring a precise air fuel mixture for optimized combustion efficiency. Fabricated from high grade synthetic elastomers, it provides excellent thermal resistance and structural