The expansion valve plays an important role in your air conditioning system’s operations. Also known as the thermostatic expansion valve, it’s found on the evaporator coil. As coolant travels from the condenser coil to the evaporator coil, it must pass through the expansion valve. The expansion valve will regulate how much refrigerant enters the evaporator coil. What happens if your air conditioning system doesn’t have an expansion valve exactly?
Overpressurized Evaporator Coil
Without an expansion valve, your air conditioning system’s evaporator coil will become overpressurized. The expansion valve doesn’t just regulate how much refrigerant enters the evaporator coil; it regulates the pressure of the refrigerant within the evaporator coil.
The expansion valve works by only allowing some refrigerant to pass through it. As the refrigerant exits the expansion valve, it will fill the interior of the evaporator coil. If your air conditioning system doesn’t have an expansion valve, there won’t be anything to stop all of the refrigerant from entering the evaporator coil. Your air conditioning system’s evaporator coil will receive too much refrigerant, resulting in overpressurization.
Lack of Cooling Power
Your air conditioning system won’t be able to cool your home without an evaporator coil. Cooling requires a rapid drop in temperature at the evaporator coil. Normally, the temperature of the refrigerant will drop as the pressure drops. The expansion valve will lower the pressure of the refrigerant within the evaporator coil, thereby allowing the temperature of the refrigerant to drop. If there’s not an expansion valve present, neither the pressure nor the temperature of the refrigerant will drop.
Refrigerant will remain hot within your air conditioning system’s evaporator. As the fan blows air over the evaporator coil, it will produce warm air that enters the ductwork. The end result is a lack of cooling power.
Lack of Dehumidification
Without an expansion valve, your air conditioning system won’t be able to dehumidify your home. Dehumidification occurs at the evaporator coil. Airborne moisture vapor will condense on your air conditioning system’s evaporator coil. This moisture will drip into a pan below, allowing it to drain to your home’s exterior.
Airborne moisture vapor, though, will only condense on a cold evaporator coil. If there’s not an expansion valve present, the evaporator coil will remain warm. Therefore, dehumidification won’t occur. You need a functional expansion valve to lower the pressure and temperature of the refrigerant as it enters the evaporator coil.