An equalizer line on a TXV is used to:

• A. Increase refrigerant charge
• B. Compensate for the pressure drop across evaporator coil
• C. Maintain superheat
• D. Stop refrigerant flow

Answer: (B)

An equalizer line helps the TXV sense the pressure at the evaporator outlet, not just the upstream pressure. In many evaporators there’s a noticeable pressure drop from the coil inlet to the outlet as refrigerant absorbs heat. If the valve only sensed the inlet pressure, it would misread the actual evaporating conditions and could feed too much or too little refrigerant, causing poor heat transfer and unstable superheat. By tying the sensing point to the evaporator outlet, the TXV can compensate for that pressure drop and maintain the desired superheat at the evaporator exit. It doesn’t increase refrigerant charge or directly stop flow; its job is to ensure accurate sensing and stable operation across the evaporator.