Can anyone point me in the right direction for sizing an expansion tank for a hydronics system? I followed a step-by-step calculated procedure by hand with a mentor once about a year ago, but he's not around at the moment for me to turn to. I found calculators online, but I was hoping somebody here may be a able to direct me to the method that requires multiplying each pipe size's total lineal feet by a conversion factor and summing the totals to get a volume.