How many operating pressures are there in a thermostatic expansion valve?

A thermostatic expansion valve (TXV) operates based on two crucial pressures: the vapor pressure of the refrigerant in the evaporator and the spring pressure that controls the opening of the valve itself. The valve regulates the flow of refrigerant into the evaporator, maintaining efficient cooling.

While there are indeed two operating pressures involved, it's essential to consider that additional factors, like the superheat setting and various operational conditions, can create further dynamics within the system. However, the primary operating mechanism relies fundamentally on the balance between these two pressures, which make it seem like there may be more functionalities at play, but ultimately, it is centered around these two core pressures.

If the focus were strictly on standard operating principles, suggesting there are four operating pressures could misrepresent the mechanics involved. Therefore, stating that there are three could imply an incorrect understanding of how the TXV functions.