Thermostatic expansion valves are rated in which of the following?

Thermostatic expansion valves (TXVs) are primarily rated in terms of their capacity to handle specific amounts of refrigerant, which is measured in tons of refrigeration. This measurement relates to the cooling effect that the valve can provide, making it a critical factor in the selection and application of TXVs in HVAC systems.

While superheat settings and horsepower may be relevant in the context of how a TXV operates or interacts with other components of a refrigeration system, the main industry-standard rating that guides the operational capacity of thermostatic expansion valves is indeed in tons of refrigeration. This rating helps ensure that the selected valve can effectively control the flow of refrigerant in response to the cooling demands of the system, maintaining efficiency and performance.

Thus, the focus on tons of refrigeration as the rating for thermostatic expansion valves underscores its significance in accurately determining the appropriate size and functionality required for effective system performance.