The Nordyne 669822R 4-Ton Thermal Expansion Valve (TXV) is an OEM replacement component designed for compatible Nordyne HVAC systems using R-410A refrigerant. It regulates the amount of refrigerant entering the evaporator coil by adjusting flow according to cooling demand and operating conditions. This valve is used in compatible air conditioning systems and heat pump equipment, helpi... https://www.partshnc.com/669822r-nordyne-4-ton-thermal-expansion-valve-txv-r-410a