What type of service are three-way valves primarily associated with?

Three-way valves are primarily associated with mixing service because they are designed to control the flow of two different fluid streams in order to achieve a desired temperature or flow rate from the combined output. In typical applications, one input may carry a cooler fluid (such as chilled water) while the other input carries a warmer fluid (such as heated water). By adjusting the position of the valve, the operator can mix these two streams to achieve an output that meets specific thermal or flow requirements.

This functionality is crucial in systems such as heating, ventilation, and air conditioning (HVAC) where maintaining control over the mixed output temperature is essential for comfort and efficiency. While three-way valves can also play roles in heating or cooling service, their primary use hinges on the mixing of fluids to attain the desired characteristics of the output stream.