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Replacing the Expansion Tank

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Anthony_10
Anthony_10 Member Posts: 23
in THE MAIN WALL
I have the old style expansion tank ( the big cylinder right above my heater). I want to replace it. My heater's capcity is :125,000 water input;
100,000 water output;
Net I.B.R Ratings is 87,000 BTU/hr;
What size of the newer type of expansion tanks would I need? I have a 2 story home with no radiators in the basement. Thanks for any help.

Comments

  • heatboy
    heatboy Member Posts: 1,468
    Why replace it?

    It's worked for years.......right?

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    There was an error rendering this rich post.

  • Jerry_15
    Jerry_15 Member Posts: 379


    A #30 would probably do it for you on a guess, but I agree, if it's working fine, and not showing signs of deterioration, why bother. Rather be sure that that your gauges, and relief valve (I see many 125psi valves slugged in; now THAT'S a quick fix), that your pressure is correct and not making big swings during heating cycle.
  • Brad White_79
    Brad White_79 Member Posts: 11
    I am going to assume you have a good reason to replace

    the tank. Perhaps an annual if not constant ritual of venting air out of radiators, watch the relief valve drip, then draining the expansion tank to repeat the cycle. Maybe some other reason and not for "no reason at all".

    As Jerry and Jeffrey suggest, if not a problem why touch it. I will assume you must for whatever reason.

    And I am also going to assume that you are pumping away from the expansion tank connection point and if the Gods are taking notes on your behalf, you have a good air separator. Are these things in place? Start there before you replace the tank to solve a pressure problem.

    Jerry's suggestion is close to my own but I would want to calculate it. Joe Mattiello from Taco posted a nice spreadsheet designed to select (IIRC) a replacement diaphragm tank for a conventional tank.

    You should know the approximate volume of the system. A converted gravity HW system with large pipes and large volume radiators may over-power a #30. But let's face it, at less than $40, buy two and install them manifolded to a common connection point is cheap insurance and less money than a single larger tank such as #40 or a #60.

    On some converted gravity HW systems I have needed three. If you think you have a small volume system (copper tube and fin tube) a #30 may well work fine.

    Brad
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