Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Steam boiler feeds automatically (unwanted)

I have a steam boiler that has a hot water feed (off the hot water heater). Between the hot water heater and boiler, I have a 1/4 turn valve that I open to feed the boiler with hot water when needed. Lately, the boiler has been getting feed water automatically. Is it common/possible for a 1/4 turn have a leak and cause this to happen?

Please let me know your thoughts.


  • Bruce Stevens
    Bruce Stevens Member Posts: 133
    Yes it is possible

    I am assuming that your water heater is gas or electric, if it is a tankless coil in the boiler that is also an option, or if the tankless coil is being used as a hot water zone with a feed valve. I am also assuming that there is no auto feeder hooked to your boiler, another possible cause.
  • Ken_40
    Ken_40 Member Posts: 1,320
    The above post is

    absolutely correct. Of some note; the hot water is NOT helpful. Hot water is far more aggressive on valves that cold and all feeders installation instructions tell us NOT to use hot feed water to a boiler feed-line.

    The old wive's tale of reducing "thermal shock" by feeding with hot water is just that. The awareness of feeding a boiler any water at any temperature back in the day commonly caused boilers to crack. What they didn't tell us was that frequently, the boiler was empty and had NO WATER AT ALL! Cool or warm water would have also cracked an empty boiler. The notion of using warm water as a way to overcome cracking was begun. Thermal shock is NOT an issue with a low boiler water condition - needing a fill.

    As an aside, you should not have to add water more than once a month in fall or winter, maybe once every two weeks in the dead of winter. If this is NOT the case, you have some system leaks that must be repaired or the boiler life and economy of operation will suffer greatly.

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
  • Ralph Trentacosta_2

    Yes the Hot Water Heater is gas. No auto feeder is installed. Only auto cut off.

    Also, are you guys saying that it does not help, but rather hurts the boiler, to feed it with hot water?

  • Ken_40
    Ken_40 Member Posts: 1,320

    I'm not sure it "hurts" the boiler, but the anode disolves into the water which goes into the boiler which is yet another "foreign" compound therein...

    We know hot water feed valves are short lived compared to cold water feeds.

    Maybe I am suggesting hot water feeds hurt boilers.

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
  • Dick Charland
    Dick Charland Member Posts: 178

    Ralph, the best thing to do is to install a union below the valve and above the water line, break the union and see if there is any water dripping by the valve when it is off. This is most often referred to as a broken union test.
  • RJ_4
    RJ_4 Member Posts: 484
    cross connection

    What ever you decide, it sounds like you have a cross connection, you should have a backflow device in the line between your HWH and the boiler.

    There was an error rendering this rich post.

This discussion has been closed.