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.

Boiling water in hydronic baseboard heating sys

Dr_Aculas Member Posts: 6
I have a problem if someone can please help me. Me and my wife have an old house and it came with a hydronic heating system (i believe thats what its called). We have a boiler in the basement with pipes running along the baseboard on mostly every wall in ever room. Now on the second floor the 2 verticle pipes leading to the third floor is making a noise like crackling. So i grab it to feel it and it feels like the water in boiling in these pipes. I shouldnt say feels like it, IT IS BOILING. i know when something is boiling and that is exactly what it is doing. Now the previous owners painted over these pipes like 3 times so thats how i am able to grab them to feel it. Its not air, it is boiling up. I know this cant be good so i lowered the aquastat to the lowest setting and its still doing it. Help please. My wife believes its going to burst. Also there is a buzzing noise coming from the aquastat in the basement connected to the boiler. If anyone has ever had these problems and can give me steps to correct this it would bę greatly appreciated. Thank you.


  • mattmia2
    mattmia2 Member Posts: 9,738
    what does the tridicator on the boiler say?
  • unclejohn
    unclejohn Member Posts: 1,833
    First of all it's my wife and I. Now you say you held on to a pipe that at 10pisg will be 240* F.
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
    It’s not boiling on the second floor if it’s not boiling in the basement.
    Nothing anyone can do here to help, too ambiguous and not enough info. Not even sure if it’s water or steam.
    Best to get a hydronics pro over there pronto., right?

    There was an error rendering this rich post.

  • SuperTech
    SuperTech Member Posts: 2,185
    The buzzing on the aquastat is quite common. The relay is getting worn out.
    If the water was actually boiling you would have burner your hand, unless you grabbed it while wearing a welding glove. It would be quite obvious that the boiler is overheating in the basement, and you would hear it from all the pipes.
  • neilc
    neilc Member Posts: 2,707
    and the boiler would be puking all about the basement also
    known to beat dead horses
  • Icarus
    Icarus Member Posts: 143
    edited February 2020
    MY guess is that you have air in the system, and it is speaking the highest point. Probably not boiling, just sounds like it. Gonna feel hot at 130f. If it was actually boiling, you would be puking water/steam out the pressure relieve valve. (If there is none...you got bigger problems)

    At the end of each hot water baseboard (under the cover) you should find a bleeder valve. Open the valve Just a touch with a towel around it (watch out for hot water scalding) and you should have a burping of water/air mix. Start at the lowest, move to the highest. If it is only on the 2nd/3rd floor do those and see what happens.