The equalizing line in a thermostatic expansion valve helps balance pressure drop between which component?

• A. Evaporator
• B. Condenser
• C. Compressor
• D. Refrigerant line

Answer: (A)

The equalizing line is connected to the evaporator outlet so the valve senses the pressure at the evaporator itself. As refrigerant moves through the evaporator, pressure drops along the coil. If the valve only “saw” the high suction pressure at the compressor, it could overfeed or underfeed as those drops occur. The equalizer provides a pressure signal from the evaporator side to the valve, balancing those pressure drops and allowing the valve to respond to the actual evaporator pressure. This keeps the superheat control accurate and the flow stable.

So, the equalizing line balances the pressure drop across the evaporator.