Position of three way valve in CWS

[hamidpia]

Why three way valve is installed on the return side of Chilled water systems and on the supply side of hot water systems. Best regards.

[bruceboldy]

The standard practice of my company, Trane is for 2 way or three way valves to be on the outlet side of a liquid evaporator coil. The reason for this is to alleviate the chance of air accumulating in the coil when off cycle. i am sure their are a few other thoughts on this, but this is the biggest reason.

regards

bruce

[Brian_UK]

Which type of valve are you asking about, diverting or mixing?

Also, before or after the pump?

[Lowrider]

The reason they are installed diverting in cooling systems is to ensure flow through the entire system. The only way to get the valves to mix is to install them, in the correct position, in the return line.

To get the heating system to work correct, they have to be installed in the feeding line to get the return water to help "cool" the feeding line off a heating group in order to get the right temperature, since most system calculate the main feed temperature on outside temperature (a so called outside temperature dependend control) or on bassis of a calculated needed temperature. Since heating groups for radiators need a higher temp then those of ahu's the need arises to get the cooler then the supply temp, hence the mixing valve!

Hope this explains it for you!