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Hydronic system flushing - how often?

28W Member Posts: 141
When I converted from oil to gas this year, the installer did a thorough flush of all the piping and radiation (baseboard and convector) prior to installing the new boiler.  Should annual maintenance include flusing the system? 


  • Tim McElwain
    Tim McElwain Member Posts: 4,628
    Not on a FHW system

    in fact I am a big fan of water treatment which once done should last a long time. Fresh water is the enemy to a system,
  • icesailor
    icesailor Member Posts: 7,265

    Especially if the water has a low PH (well below 7.0) and there is nothing in the boiler/system to buffer the water up.

    Orange boiler water can be a very bad thing.
  • bugaboo
    bugaboo Member Posts: 14
    Not a good idea

    An annual flush will lead to a rotten boiler.

    When water is introduced into the system it carries "free" oxygen. This free oxygen will combine with the iron in the boiler and create rust. Once all of the free oxygen has combined with the iron the rusting will stop. Any time you add fresh water you add free oxygen and cause more rust.

    Leave it sealed and you are all set.
  • 28W
    28W Member Posts: 141
    Alrighty then!

    Thanks for the great advice, guys. One less thing to worry about.
  • CMadatMe
    CMadatMe Member Posts: 3,086
    Low Loss Header

    You have a LLH installed in your system. Any debris in the system is going to fall to the bottom of it. At service time, you simply blow any debris out at the provided boiler drain.

    There was an error rendering this rich post.

  • 28W
    28W Member Posts: 141

    Is it as simple as opening the drain, or does "blowing out" the debris involve pressure? I'm not going to do the service, but I am curious.
  • Paul48
    Paul48 Member Posts: 4,469

    Your system is under pressure.
  • 28W
    28W Member Posts: 141
    D'oh! Of course it is

    Thanks for clearing that up. I forgot about that.
This discussion has been closed.