2 Gallon Expansion Tanks...Hot water VS Well expansion tank

Discussion in 'Water Heater Forum, Tanks' started by Its.me.again, Oct 12, 2012.

  1. Its.me.again

    Its.me.again New Member

    Messages:
    7
    Location:
    Buffalo, NY
    Can anyone solve this mystery for me? When it comes to putting a 2 gallon thermal expansion tank on a hot water heater, can a person opt to use a 2 gallon well pressure expansion tank?

    What is the difference between these expansion tanks?

    I will use the following example that Lowes sells the 2 gallon hot water tank expansion tank for $40.00 and the 2 Gallon well pump expansion tank for $50.00. These are the "LPT2" series tanks.

    I wonder if most people complain that typical hot water expansion tanks experience bladder failure in 3 years? Do you think that the well style expansion tank has a stronger internal bladder and will last longer?
  2. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,825
    Location:
    Cave Creek, Arizona
    They should be the same tank, because a 2 gallon "well pump expansion tank" would be absolutely useless for a pump system, (and well pumps do NOT have an expansion problem in the first place).
  3. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,055
    Location:
    NW Ontario, Canada
    A 2 gallon pressure tank on a well pump would be fine for a sprinkler system that is matched to the GPM of the pump so that it doesn't cycle. Also would work with a CSV.
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,138
    Location:
    New England
    WH expansion tanks are designed to be installed on the cold water supply and won't work well on the hot side - the bladder dies earlier. Both a well tank and a WH would normally only have cold water feeding them, so, it's likely either should work. A well tank bladder would probably see MUCH more expansion/contraction of the volume of water, and to survive a decent service life, the bladder may be more robust to take the regular large excursions as the pump cycles. A WH, depending on its size, may only need to accommodate a cup or so from expansion, a well tank much more.
  5. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,358
    Location:
    Yakima WA
    Interesting you found a thermal expansion tank at Lowe's. My Lowe's doesn't even know what they are. That aside, I have had my expansion tank in place for 5 years and it is still just fine.
  6. zl700

    zl700 DIY Senior Member

    Messages:
    237
    Location:
    Texas
    Unless its on a variable speed constant pressure well system or a jet pump booster system and then 2-gallon well tanks are the norm.
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