Posted 2/18/2017 08:01 (#5847460 - in reply to #5847423) Subject: RE: don't want to hijack the thread but
Driftless SW Wisconsin
That device is an expansion tank so the system water can expand or contract with temperature changes. My system has an expansion tank and is connected to the house cold water system through a couple check valves so it fills automatically if needed. Seems to me you need some way for the system water to expand or contract. There's a lot of tubeing there going through a lot of temperature changes.
Adding water to in floor heat system
