The Carrier 332368-754 R410A Thermal Expansion Valve (TXV) is a critical component in HVAC systems that controls refrigerant flow. This valve, which is installed in heat pumps and air conditioning units, effectively regulates the amount of refrigerant that enters the evaporator coil. The refrigerant changes phases as it travels through the TXV, going from a liquid to a gas, which is necessary for the cooling process.