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over sized expansion tank

I have a 2.5 gallon electric tank water heater that requires an expansion tank, the smallest tank i can find is 25% larger than needed. will the tank essentially be useless or can it still be installed without causing issues with T & P valve or can we lower the pressure in the tank or is there another option we can use to appease the code official requiring an expansion tank.



Comments

  • Zman
    Zman Member Posts: 7,330
    There is no downside to an oversized tank aside from cost.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    Canucker
  • Jamie Hall
    Jamie Hall Member Posts: 18,941
    Zman said:

    There is no downside to an oversized tank aside from cost.

    In fact, it's good. Reduces the pressure variations in the system.

    Don't change the pressure in the tank from what is recommended in your setup.

    And as for appeasing the code enforcement official -- that's not what the tank is for. It's to prevent catastrophic failure of your water heater or plumbing system from over pressure.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Dadgineer
    Dadgineer Member Posts: 2
    thank you for the input.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 12,002
    Remember to adjust the air pressure in your new expansion tank to match the water pressure in your water system.

    You must do this with no water pressure on the expansion tank bladder
  • HVACNUT
    HVACNUT Member Posts: 4,593
    > @EBEBRATT-Ed said:
    > Remember to adjust the air pressure in your new expansion tank to match the water pressure in your water system.
    >
    > You must do this with no water pressure on the expansion tank bladder
    >
    >
    > Just to add to that, if you don't have a pressure gauge, maybe the Water Authority can test your incoming pressure. Then use a compressor, or take it to an air pump at a gas station, and charge the tank to match the water pressure in PSI.