Three-pipe system design

[dblyle]

We are currently replacing the chillers and controls in a three-pipe system - HW supply, CHW supply and common return. Has anyone seen a system like this before and can you give me a sequence of operation? I am trying to decide if we need another by-pass on the chill water side to allow the chillers to run to cool the loop once we switch from the hot water side.

/dbl

 

[HEC]

dblyle,
I am having trouble following the pipe plan you attached do you have a P&ID of the system?
What is the process that you are servicing with hot and cold water?
With this information we can probably provide an answer.

Mark Hutton

 

[willard3]

The first thing you want to do is make sure the water coming to the chiller is less than 75F or the chiller will trip.

This is a proprietary system and it runs badly if you change from heating to cooling mor4e than once a year.