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expansion tanks

targetman Member Posts: 105
What would be the effects of an oversized diaphragm- type expansion tank.


  • Viess
    Viess Member Posts: 58
    Waste of money?

    Not a pro but I would only be concerned if it were to small. To small and you will cause the system to over pressurize and possible wear out the diaphragm sooner thereby causing the boiler safety value to open. Size the tank according to the system volume and the systems max boiler water temperature. Don't see a real problem with an over sized tank other than initial cost. Viess.
  • hot_rod
    hot_rod Member Posts: 21,862
    no problem

    as long as the pre-charge pressure is adjusted properly.

    Some of the solar expansion tanks on the market come with a 60 psi pre-charge so it is very important to check the pressure regardless of what the label may say.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
This discussion has been closed.