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Gas Boiler Chemical Clean Help

DeWolf Member Posts: 1
I need a little assistance with doing a chemical clean on my 50 year old Weil McClain. All the copper under my slab has bit the dust and I am replacing baseboard lines with PEX. My boiler has started percolating and before I fire up the new system, I want to do a chemical clean. My question is, should I circulate the chemicals through the old copper right before shutting down for the season ( and replacing the copper) or is there a way to drain the boiler, directly add the chemicals and then circulate the pump into buckets? Any help would be great.


  • Zman
    Zman Member Posts: 6,983
    I think it depends on how your boiler is piped. There is likely a simple way to do a bypass at the boiler.
    You should also have "Plan B" (replace the boiler) in place. There is an excellent chance that the scale you are removing is all that is holding it together.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • hot_rod
    hot_rod Member Posts: 15,027
    Also make sure that the system is leak free. A lot of hard water mineral build up, usually the cause of percolation sounds, may indicate a small leak in the system.

    I've used Hercules Sizzle for boilers with a lime scale build up, both cast and copper tube style. Follow the mix instructions carefully.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream