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vents on Mains

alanm Member Posts: 71
I have a house built in 1896 that originally used coal as the heat source . At some point, they switched it to oil. system never seemed to work well (short cycling, uneven heat, etc). There is , I believe a return vent (see photo) , at the heater but with all the mains running in the basement, there are no vents on them . Should they have them and if so, could this be causing the problems?


  • BobC
    BobC Member Posts: 5,478
    That is a Hoffman 75 vent and it might be to small, also it looks like you have 2 mains and there should be an air vent towards the end of each main to vent the air quickly. Tell us how long each steam main is and what size pipe so we can tell you how much venting you should have.

    Another issue is the copper pipes coming off the boiler header are too small. They should be steel and they should be the full size of the steam mains (look to be 2").

    Is this a single pipe steam system? If so what kind of vents are on the radiators?

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge