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Expansion Tank in Attic

Have a customer with two Weil Mclain CG3's boilers that need replacing, Plan on going back with 2-WM CG-3's PIDN, The expansion tank is now in the attic (see note below) I had planned on installing two extrol tanks at the boiler and remove what is in the attic. Is what the customer is saying correct, I was taught that at one time it was a open system and that when filled the water would show up coming out onto the roof, but when switched over the system became a closed system, I would think that if each radiator was not bleed out that they would have a good amount of air in each radiator. That removing the expansion tank in the attic and installing the extrol tank at each boiler is the proper way. See what she says below, Everyones input would be great.

I think it is better to keep the units separate to the extent possible so tenants can maintain some control over their energy use.and bills. Having a single boiler to heat water would mean that either one boiler paid for by one tenant or a bigger boiler with a split bill is run all year to heat water. There are gas stoves also. I am trying to realize net energy savings for each unit. Having the expansion tank in the attic allows the air to rise to the highest point in the system. It saves trying to open painted valves covered by built-in radiator covers.Elaine



  • JStarJStar Member Posts: 2,668

    That's not true. Air will get to the radiators no matter what you do in these old radiator based systems. I would much rather have a closed water system to avoid rust and corrosion.
    - Joe Starosielec
    [email protected]
  • icesailoricesailor Member Posts: 7,265

    And they didn't all overflow on the roof. In fact, where I work, I never saw one that drained on the roof. There was a overflow pipe that ran to the cellar near or at the boiler and when the tank was overfilled, it overflowed to a drain in the cellar.
  • Paul48Paul48 Member Posts: 4,231
    edited February 2013

    Was next to the stack, and drained in the stack. Air will have to be bled from the radiators at some point, especially if the system has been drained.If the bleeders don't work, they need to be replaced.
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