New Expansion tank installation....necessary ?

Discussion in 'Water Heater Forum, Tanks' started by rcatty, May 25, 2009.

  1. rcatty

    rcatty New Member

    Messages:
    15
    Location:
    Illinois
    I have a well, and just installed 2 new hot water tanks (50 gallon each). The system, besides being on a well, has a hot water recirculating line, with a grundfos pump, and a checkvalve (on the recirc line only).

    My cold water line, traced back to the well, has a main shut off valve, wiring for the well pump, and a "dial/degree" shut off valve where the water line enters the house. I see no checkvalves or other items in the line.

    Do I need to install a thermal expansion tank ? If so, the manufacturer instructions all indicate that the tank should be placed between the tank shut off valve and the tank itself. However, my shut off valve is located only about 5-6 inches from the tank. That leaves me a narrow spot to install the tank. Indeed, that area of the cold water inlet line often gets warm from the heat of the tank. Is it safe to install the tank at that spot? I can cut into that 3/4 inch pipe, place a tee, and extend a pipe out, and put a 90 degree with a female end and strap to the ceiling.

    Is it safe to install a thermal expansion that close to the top of the tank itself? Thank you
  2. SewerRatz

    SewerRatz Illinois Licensed Plumber

    Messages:
    1,706
    Location:
    Chicago, IL
    It shouldn't hurt at all. Maybe post a pic of your set up.
  3. kingsotall

    kingsotall Plunger/TurdPuncher

    Trying to see if they have the tanks piped in parallel or series, Ron¿ ;)
  4. SewerRatz

    SewerRatz Illinois Licensed Plumber

    Messages:
    1,706
    Location:
    Chicago, IL
    No matter really, each water heater needs an expansion tank. But it would be nice to see :D
  5. kingsotall

    kingsotall Plunger/TurdPuncher

    This OP has some nice descriptions of their setup. It is obvious there is some thermal expansion by the cold inlet being warm but they should consult their county code. Ours requires expansion tanks even without PRV's or checks in place. :confused:
  6. SewerRatz

    SewerRatz Illinois Licensed Plumber

    Messages:
    1,706
    Location:
    Chicago, IL
    Ours is going to start to require it. It mainly due to many villages putting in new meter yokes with built in duel checks. So they want the water heaters to already have the proper protection.
  7. kingsotall

    kingsotall Plunger/TurdPuncher

    Makes sense. The fellas I work with will still think it's malarkey.
  8. rcatty

    rcatty New Member

    Messages:
    15
    Location:
    Illinois
    Each tank needs an expansion tank? They are in parallel. How close can they be placed to the tank? I only have about 5 inches between the shut off valves and each tank.
  9. SewerRatz

    SewerRatz Illinois Licensed Plumber

    Messages:
    1,706
    Location:
    Chicago, IL
    Close is not a problem. Some people put the expansion tanks a tad to far from the water heaters.
  10. 99k

    99k Radon Contractor and Water Treatment

    Messages:
    460
    Location:
    Fairfield Co.,Connecticut
    Each tank must have an expansion tank, if you ever close that ball before the tank (otherwise the water will either puke out of the TNP valve from thermal expansion or may damage the tank during cool down). As it is, if you never shut the valve off before this tank (unless to replace the hot water heater) you really don't need an expansion tank (unless your code insists upon it). The reason being that the large diaphram tank for the well is acting as an expansion tank for both water heaters and accommodates any thermal expansion and contraction from the hot water heaters.
  11. rcatty

    rcatty New Member

    Messages:
    15
    Location:
    Illinois
    What is the function of that large tank for the well. Is well water stored there for later use? Would you still recommend an expansion tank? If so, is it ok to place it about 2-3 inches above the inlet valve from the hot water tank ? Thank you.
  12. 99k

    99k Radon Contractor and Water Treatment

    Messages:
    460
    Location:
    Fairfield Co.,Connecticut
    The water tank is a resevoir that allows you to store pressurized water in your home and prevents short cycling of the well pump. There is no harm installing a small pressure tank. My experience in our area is that most homes on a well do not have the small expansion tank since the larger well tank is performing the same purpose.
  13. rcatty

    rcatty New Member

    Messages:
    15
    Location:
    Illinois
    Thank you for your answer. Assuming I were to put a tank in, can it be as close as 2-3 inches from the cold water inlet valve? Thank you, again.
  14. 99k

    99k Radon Contractor and Water Treatment

    Messages:
    460
    Location:
    Fairfield Co.,Connecticut
    That is Fine.
  15. rcatty

    rcatty New Member

    Messages:
    15
    Location:
    Illinois
    Ok, thank you. Finally, do I need a pressure relief valve, and pressure gauge on the tank lines? Or can I use the pressure reading on the well pump apparatus? Thank you.
  16. rcatty

    rcatty New Member

    Messages:
    15
    Location:
    Illinois
    The Illinois Code only requires an expansion tank on closed systems.

    I don't see any check-valves on the line running back to the large tank. Is there anything I need to look for? Or, on well systems do they never put a check-valve before the large well tank?

    Thank you
  17. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,814
    Location:
    New England
    Many pumps have a check valve in them at the bottom of the well. It is not recommended to have more than one, but people sometimes do that if the one in the well fails and they don't want to pull the pump to fix it (that doesn't always work, either). If you install an expansion tank for the WH, it can go anywhere on the cold inlet line between the shutoff valve and the tank. You can run the outlet of the T a ways to make installation of the tank easier, but the T must be between the inlet and the valve.
  18. SewerRatz

    SewerRatz Illinois Licensed Plumber

    Messages:
    1,706
    Location:
    Chicago, IL
    Most well pumps will have a check valve at the pump. Illinois is going to start to require them no matter what. Yes at this point in time it is only required to be installed on a closed system.
  19. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,264
    Location:
    Cave Creek, Arizona
    expansion

    Your well's storage tank is a "large" expansion tank and will perform exactly the same function as an expansion tank at the heater, except when the water supply is off to the heater and the water is being heated, which is not a normal situation and will seldom happen anyway in the normal course fo events.
  20. HJ...... finally got it right


    You dont need an expansion tank on a well,
    as HJ already stated it is not necessary because you already
    have a huge well bladder that is doing the same exact job for you

    considering that most wells are normally around 50-60 lbs,
    the water pressure will never rise high enough on a well to ever
    cause the pressure relief valves to ever pop off in the first place
    It simply CANNOT pop off because you have the well tank as a huge back up...........


    so just save your money ,
    or better yet take the wife out to dinner with it.
    (dont tell her why)..
    Last edited: May 27, 2009
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