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If you see this boiler a-rockin...

Hey guys,

Maybe not-so-quick question, albeit probably a pretty common one, has anyone out there know what's causing a boiler to really shake the floor when it first fires up, and radiators that clang a lot? The boiler doesn't seem to stay on for very long, but that could be bad placement of the thermostat (being just down the hall from the strongest radiator). There are cooler pockets upstairs, but I expected that with a radiator. Overall, not bad temperature management.

Thanks and let me know if more details are needed.



  • More details needed

    What sort of system is this?

    When your system was first installed many years ago, it was silent and even heating, so what has happened since then?--NBC
  • Newtosteam
    Newtosteam Member Posts: 3
    just bought house

    Single-pipe radiators. Not sure about the history of the system - we just purchased the house this past spring and are completely green when it comes to steam heating (if that's not evident enough, ha ha!). It's a Peerless boiler, and we didn't have to fire it up all that much then; when we did, there was some banging then, but nothing that shook the floor. It was just recently serviced by a plumber, who did the usual seasonal servicing and replaced all the valves on the radiators. The shaking seems to be worse when it first kicks on after not being on for a bit.
  • New valves

    What vents are now on the radiators, and did you keep the old ones, in case you have to reinstall them? What sort of main vents are on now?--NBC
  • Steamhead
    Steamhead Member Posts: 16,718

    what model Peerless boiler?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • BobC
    BobC Member Posts: 5,471
    Oil fired boiler?

    If this is a oil fired boiler and it fires up with a bang it could be delayed ignition. that could be crud in the spark gap or a weak ignition transformer.

    If the racket doesn't start till the boiler starts to make steam it could be a number of things all involving water hammer. That means you have water sitting in pipes where it shouldn't be. Make sure all the piping has consistent slope and don't trust your eyes, use a level. Also check the radiators to make sure they have a slight slop back towards the input valve.

    The fact it doesn't run long may mean your air vents on the steam main are not working, look for them and make sure they are working. It may also indicate your boiler is to big for the amount of radiators you have.

    Your piping should resemble one of these images below.

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