Originally Posted by NHMaster
Beg to differ. You are using the right size for the total head pressure on the system with thermal expansion compensated for. Why use a tank that is too small. There is a 15 dollar difference in price.
Sole purpose of an expansion tank is a place for the water to go to when it expands. To prevent excess pressure build up. It isn't suppose to prevent the pressure from rising. A 3 PSIG rise is ok.
Nothing wrong with using a 60 on a system that only needs a 30.
Or a 90 on a system that only needs a 30.
Even on the old open vent systems. A 1 or 2 PSIG rise was normal.