Insulating a Expansion Tank

[sdrobertson]

Could someone post the formula to figure out how many gallons of water will move into an expansion tank. I have 2000 pressurized gallons and I need to know how many gallons of water will move to and from the expansion tank and how fast from 130 degrees to 180 degrees. My expansion tank is in a insulated boiler room and I don't really want to insulate the tank itself as I have to be able to see the gauge, so if it isn't allot of water, I'll just live with the heat loss.

 

[jebatty]

You can find this on Google. Precise answer is pretty close to 4%, and varies depending on start and end temps. I tend to use 5% as a rule of thumb, which comes pretty close to 50-200 range.