Please proof this article: An Overview of Water Heater Expansion Tanks.

[gromicko (Nick Gromicko, CMI)]

http://www.nachi.org/water-heater-expansion-tanks.htm

[dhadler (Darrell B. Hadler)]

Looks fine to me

[jevans (John Evans)]

To be installed on the cold water supply.

[rperkerewicz (Ron E. Perkerewicz)]

2nd paragraph change Air is used as a cushion since it will compress and water does not therefore it exerts less force on its container than water.

[lgreen (Loren Green)]

Not a Substitute for a Temperature Pressure Relief (TPR) valve.
This sentence is missing a noun.

[rmcdonough]

The article looks great!