What is the purpose of an equalizer line in an evaporator circuit?

• A. Increase efficiency
• B. Balance pressure between inlet and outlet
• C. Reduce energy consumption
• D. Improve condensation

Answer: (B)

The equalizer line brings a signal of the evaporator outlet pressure back to the metering device so the expansion valve can respond to the actual pressure across the evaporator. In many evaporators, pressure drops from the inlet to the outlet due to flow resistance. If the valve only senses the inlet pressure, it can overfeed or underfeed as conditions change along the coil, causing unstable superheat and uneven cooling. The equalizer ties the valve to the outlet pressure, helping to balance the pressure between the evaporator’s inlet and outlet and keep the refrigerant flow steady. This is why its primary purpose is balancing pressure between inlet and outlet. It doesn’t directly make the system more efficient or improve condensation; it improves control and stability of the evaporator operation.