By Chad Edmondson

 As we bring our first series about air management in a hydronic system to a close, we’re going to revisit tanks – not what they do (we’ve already covered that) but what we call them.  Specifically, we want to address whether or not there is a difference between what some industry professionals call an “expansion tank” and what others call a “compression tank.” 

By Chad Edmonson

Properly sized expansion tanks (standard or bladder/diaphragm) are critical to a successful air management in a hydronic system.

Every expansion tank manufacturer has a written form that provides the steps and calculations for sizing an expansion tank.  Most, if not all, have developed software that does the work for you.  Bell & Gossett has a great one, ESP-Plus which can be downloaded here.  But regardless of whether you use software or charts and longhand calculations to size an expansion tank, there are a few pieces of information you’re going to have to have either way.  These key values are:

By Chris Edmondson

 Air must be managed in every type of closed hydronic system, either by (1) routing it to a specific place in the system where it can’t create problems like pipe corrosion or air blocking of components, or (2) by continuously eliminating it