replacing expansion tanks

Jeff Bolton

This is my first post on the wall. Did I do it wrong or did I ask a good question?

Jeff Bolton

replacing old style expannsion tanks with bladder expansion tank

This morning I ran into an interesting problem. I was at a 21 stoery apartment block where my customer needs to change the expansion tanks. Currnetly there are 2 old style tanks with and outside dimension of 30" x 86". They are about 1/2 to 3/4 full by the gauge glass. I have figured out that they have a total volume on 263 galllons. I know that I have an output of 5 million BTU from the boilers. My system PSI is 95 so in our area we need an ASME rating. Should be easy to figure out right, but one important piece of information eludes me. THE TOTAL SYSTEM VOLUME! In an older building like this there is know way to get this info that I know of. Draining the system is not an option for various reasons. Manufacturers will not help without knowing the total system volume. I have sheets that will tell me new bladder stlye sizing by dimensions but they are for non-asme and they only go up to 1.6 mil. As well it seems to me that the acceptence volume changes drasticly between non-asme and asme tanks. So, Am I the only one that has run into this problem or is there a way to size my tanks?

Any help would be greatful.

Empire_2

This should help:

Although total volume is needed, it can get you on your way.

Mike T.