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Feeding the steam boiler after running

nmquirk Member Posts: 23
edited January 2020 in THE MAIN WALL
Last night I heard the auto-feed trigger maybe 5 minutes after the boiler had stopped running (normal operation). Should I be concerned?

I've heard mention of damage happening when water is added to a hot boiler. I've also heard that's mostly a concern if the boiler had been running dry. Seems to me wet or dry is risky. I'm more interested to know how risky my situation is and are there any concerns I should have.



  • EzzyT
    EzzyT Member Posts: 1,297
    This a steam or hot water boiler? Both steam or hot water boilers shouldn’t require any make up water if so there is a leak somewhere in the system or on the boiler.
    E-Travis Mechanical LLC
    EBEBRATT-Ed Member Posts: 15,839
    If it's steam a water meter installed on the water feeder is a good idea.

    It's common for a steam system to need a little water occasionally..........It's not water being added it's how much water is being added is the issue. Water can be lost through air vents etc.

    Water being added after the burner is off could mean partially plugged returns.

    So your issue could be completely normal or it could be a problem.....depends on how much water is added.
  • Fred
    Fred Member Posts: 8,542
    Also, to answer your question, the water line should be installed somewhere on the return pipe going into the boiler. There is no risk of thermal shock because the cold water is tempered by the return water in the system.
  • motoguy128
    motoguy128 Member Posts: 393
    Most feeders also have small 1/2” lines and the valve is further restricted and shouldn’t feed more than maybe 1/2 gallon at a time. I
    Added .2 gallons yesterday manually using the manual button and it raised the line about a 1/2”. It had to travel through almost 18” of 1”& 2” pipe to reach the boiler. Plus the 3’ of the 1/2” line itself is warm.

    I’d have to add maybe 2 folks before any cold water reaches the boiler. Even then we’re talking maybe 1.5gpm

    However, best if it’s tempered by return condensate when possible.