While the regulator itself is robust

This hermetic replacement is pre-charged with mineral oil and features a high internal free volume to safely handle liquid slugging

the included orifice plate is calibrated to maintain the narrow manifold pressure requirements of the GV-6 caste iron heat exchanger

the yellow color-coding ensures rapid identification for technicians during regulator spring replacement or system commissioning

This replacement model 30685566-003 provides a leak-proof connection between the valve stem and packing assembly

Trane CNT4990 Pressure Control 320788-704 While the regulator itself isThe Trane CNT4990 is a high precision HVAC air pressure control switch engineered for critical monitoring in residential and light commercial systems. This OEM Trane replacement part features a fixed set point of 0. 26" WC, making it a vital safety component for sensing draft in inducer fan assemblies and ensuring proper airflow before ignition. With its SPST (Single Pole Single Throw) contact configuration, the CNT4990 provides reliable circuit