Where should the equalized line be connected in an external equalized TXV?

The equalized line in an external equalized thermal expansion valve (TXV) should be connected to the suction line down flow from the TXV bulb. This connection ensures that the pressure at the bulb accurately reflects the conditions in the evaporator. By placing the equalized line downstream from the bulb, it allows for proper sensing of the evaporator pressure, which is essential for the TXV to modulate refrigerant flow effectively and maintain optimal superheat levels.

When the equalized line is connected to the suction line downstream from the bulb, it helps in compensating for the pressure drop that occurs as refrigerant travels through the evaporator. This configuration allows the TXV to react appropriately to both the temperature of the refrigerant and the pressure conditions within the system, leading to efficient operation and improved cooling performance.

In contrast, the other options represent different setups that may not accurately reflect the evaporator conditions, potentially leading to improper TXV operation and inefficiency in the refrigeration cycle.