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Boiler Expansion Tank Dead End Example

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dooododoo
dooododoo Member Posts: 25
edited January 2017 in THE MAIN WALL
Question: Is this an example of an expansion tank at a dead end?



It tee's off 6 inches to the right and 90's down to a valve.

Amtrol clearly states not to install on a dead end.

They also state install the tank vertically. It is not possible with where the tee is.

Do I need to call someone out to relocate the tank?

Bonus:

Is the proper expansion tank size for this boiler a 4.4gal, such as an Amtrol 102 30lb?



(Sizing chart for Watts' ETX tanks.)

Comments

  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
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    The tank is mounted fine, and no, that's not a dead end.

    As for proper sizing, it depends on a bunch of variables, but if your pressure is staying within normal operating parameters, then I'd not worry about it. If pressure is between 12 and 27 pounds, and the pressure relief valve is not lifting, you're fine.

    ME
    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
    dooododoo
  • hot_rod
    hot_rod Member Posts: 22,143
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    looks like a domestic water expansion tank? Is it a 3/4 thread? Maybe why it tell you not to mount on dead end.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
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    @hot rod it's a heating ex tank. Domestic ones are tan I believe. Zoom in and it says boiler expansion tank on it.
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • hot_rod
    hot_rod Member Posts: 22,143
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    I thought it said Extrol. I'm use to the dark grey colored tanks. The first ThermTrols were tan like that. Or maybe it isn't tan? :)
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • dooododoo
    dooododoo Member Posts: 25
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    It's dark gray in real life. I think the flash made the color look funny. But, yes, it's for closed boiler system.
  • dooododoo
    dooododoo Member Posts: 25
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    hot rod said:

    looks like a domestic water expansion tank? Is it a 3/4 thread? Maybe why it tell you not to mount on dead end.

    No, it's 1/2"

  • hot_rod
    hot_rod Member Posts: 22,143
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    Hopefully the checked and adjusted the pre-charge pressure. That should be adjusted to the cold fill pressure.

    If the boiler is filled to 12 psi, the tank should be set to 12 psi before it is installed.

    Nice that you have a valve there to service or check the tank.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    dooododoo
  • dooododoo
    dooododoo Member Posts: 25
    edited January 2017
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    The boiler is set at 15 PSI and so is the tank (loops goes up to 3rd floor). I noticed that when the boiler is cooled down, the temp is about 40 degrees and PSI is 15. When the boiler is running and aquastat cuts the boiler off, the temp is 180 degrees and PSI is 25. Is that a normal range of PSI? Would replacing the expansion tank with a bigger one reduce the PSI change? The new tank was replaced with the same one as the old (leaking bladder) tank. The boiler is 100,000 BTU/H. I'm thinking I should have gotten a bigger expansion tank such as a 4.4gal.
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
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    dooododoo said:

    The boiler is set at 15 PSI and so is the tank (loops goes up to 3rd floor). I noticed that when the boiler is cooled down, the temp is about 40 degrees and PSI is 15. When the boiler is running and aquastat cuts the boiler off, the temp is 180 degrees and PSI is 25. Is that a normal range of PSI? Would replacing the expansion tank with a bigger one reduce the PSI change? The new tank was replaced with the same one as the old (leaking bladder) tank. The boiler is 100,000 BTU/H. I'm thinking I should have gotten a bigger expansion tank such as a 4.4gal.

    I think you're just fine. You need to stay at least 5 PSI away from the relief vale setting (30). You are there. Higher pressures are not detrimental to the components in the system. They are capable of handling much higher pressures that you are running.

    What is more important is the relationship between the pumps location in relationship to the expansion tanks.

    ME

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
    Solid_Fuel_Man

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