What size bladder tank to replace compression tank?

Brad White_33

taking into account system volume, initial PSIA, final PSIA and your tank volume selection has some "fat" in it to cover any unforseen variables, then go with it. Personally I prefer to specify multiple tanks manifolded together should one fail. But that is just a risk assessment.

Double check your calculations and proceed with confidence in them.

Joe_8

What size bladder expansion tank to replace compression tank

A customer of mine has a 120 gallon horizontal compression type expansion tank in their hydronic system. They want to replace it with bladder tank(s) (vertical area is a problem). My supplier is recommending two 57 gallon total volume, 27 gallon acceptance expansion tanks.
In doing my calculations, I came up with one 80 gallon total volume tank needed to convert. Naturally, one 80 gallon tank will cost less than two 57 gallon tanks (either way, ASME required).
So I ask all of you, and I know that you do not have all the data needed, should I trust my calculations, or is my suppliers recomendations more on the mark. Thanks for your help.

Joe Mattiello_2

Expansion tank conversion spreadsheet

Try this spread sheet out. This will help you with sizing.

Joe Mattiello
Technical Support Technician
Tel. 401-942-8000 X 484
Fax. 401-942-2360
1160 Cranston St
Cranston, RI 02920
joemat@taco-hvac.com

Joe_8

Thanks guys. You were a big help.