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Is it futile to have dry steam with an oversized boiler?

Peteys Member Posts: 79
I installed a 3 inch drop header on my 22 year old WM boiler and while it seems to make steam much faster, I'm still getting major water hammer and water in hoffman 40 radiator vents. Enough water in radiator vents that prevent them from closing while making steam.. Boiler produces 930sq ft of steam and is attached to 470sq feet of edr. Almost double.


  • BobC
    BobC Member Posts: 5,479
    Pressure and slope

    My old Burnham V75 could produce 596 sq ft of steam and i only have 210 sq ft of radiation attatched. My heat was quick and quiet but I knew it was costing me fuel because it was so oversized.

    First of all what pressure are you running at, it should be 2 PSI and hopefully a lot less. What kind of main vents are you using and are they large enough?

    Go over all the mains and radiator run-outs with a level to make sure there is enough slope so any water can find it's way back to the boiler, make sure the radiators have a bit of slope towards the steam pipe as well. Be on the lookout for any dips in a pipe that might be pooling water. Water hammer is telling you that steam is coming across standing water, when that happens it collapses 1700:1 causing the hammer and perhaps damaging your vents.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • JStar
    JStar Member Posts: 2,752
    Four Words

    Two stage gas valve.
  • Peteys
    Peteys Member Posts: 79

    Thanks guys. Running at about 12oz. with plenty of gorton 2 venting. I know I have some issues with pitch on one main 50 foot branch but this main branch is only 5 feet and is pitched properly and I believe the runouts are too. Disconnected radiators on this branch and very little water came out but hoffman 40s always have water in them preventing them from closing.

    Think I might need a pro to come out. Do you work in the Bronx, Joe. Oil fired but might want to switch to gas.

    Thank you
  • ChrisJ
    ChrisJ Member Posts: 15,767
    edited February 2014
    Hoffman 40 water

    Not sure how similar they are, but I constantly had problems like this with 10 new Hoffman 1As.

    I switched all of my vents to Gorton's and the problem went away. I believe a Gorton #4 is about the same as a Hoffman 40, going by memory. Either a #4 or a #5.

    I have a mixture of 4s, 5s, 6s and Cs depending on the location and size of rad.

    I'm pretty certain my steam is very dry. Between how the system behaves and the fact my wet return has a TDS of 1-2PPM.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • JStar
    JStar Member Posts: 2,752

    Sure do. Though, your options with oil are limited to the acceptable firing rate of the boiler. Natural gas would open up the possibility of staging.