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hydronic system powerflush?

salio Member Posts: 18
It seems the UK has a practice of power flushing hydronic heating systems. Anything like that on this side of the pond, or what is the best alternative? I'm talking about flushing out a converted gravity system before installing a new boiler.


  • EzzyT
    EzzyT Member Posts: 1,297
    edited October 2019
    @salio we have the equipment to perform the powerflushing of the radiators, system piping and boiler. The equipment that Europeans have are available here in North America.
    Every hot water boiler Repipe, replacement, installation and new system install we do gets a powerflushing
    E-Travis Mechanical LLC
  • hot_rod
    hot_rod Member Posts: 22,467
    Adding a cleaner, hydronic detergent, helps get a good clean system, oils, fluxes, etc.

    Old iron pipe systems, cast iron rads and the UK open systems are tougher to get cleaned as the heavy rust particles need a lot of gpm to move out once they are cleaned off.

    It takes at least 5 fps velocity to move heavy particles, dirt, rust, through a pipe. In a 1" pipe you need around 13 gpm to get velocities up to 5 fps. It takes a pretty good purge cart to supply that.

    I've yet to find a way to flush all the rust from old cast rads, best to keep flow below 4 fps and let the rust lie :) Rust never sleeps!

    Add a good dirt and mag sep to any of those old iron/ steel systems when you upgrade them. Especially with small passage mod con HX's.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • HomerJSmith
    HomerJSmith Member Posts: 2,509
    Before you break into the sys with a new install, run a boiler cleaner thru it, perhaps, Sludgehammer, etc. and run the old boiler per instructions.

    I use a lawn sprinkler pump to power flush the system.

    or similar pumps. It is amazing how much crap comes out of the sys when you have high flow and high head pump. Pump each zone one at a time if possible and drain thru the boiler.