The Carrier 331709-799 Thermostatic Expansion Valve (TXV) is a refrigerant metering component designed for compatible HVAC and refrigeration systems. It regulates refrigerant flow into the evaporator by responding to changes in refrigerant temperature and pressure, helping maintain proper superheat for efficient heat transfer. Commonly used in compatible air conditioners, heat pumps, ... https://www.partshnc.com/carrier-331709-799-carrier-txv