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How to flush Boiler?

Hey guys,

Quick question. I am wanting to flush out my boiler. The water is really dirty (i just noticed today). It's a Utica Boiler PEG112CIDE model. Is it just a matter of shutting it off, plugging a hose into it and draining it?


  • RodRod Posts: 2,067
    edited November 2011

    Hi- There is minor flushing and then there is major FLUSHING ! Flushing and refilling the boiler should be done with the power to the boiler OFF and when the boiler is COLD! The minor flushing is just draining the boiler and refilling it. After refilling the boiler, since you have added "new" fresh water to your boiler you want to then bring it immediately to a boiler to drive off the corrosive excess dissolved oxygen.

    You might then run the boiler for a day or two and repeat the minor flush. Depending on how clean the boiler water is then, you may want to repeat the minor flushing several more times.

    I generally don't like using additives though I have had good luck with Rhomar 9150

    Major flushing is setting up a full port drain and through a boiler port, like where the safety valve is connected, hosing down the inside of the boiler. It's a lot more hassle than doing a minor flushing and I'm not sure it's all that more effective.

     You should also flush your wet return as being the lowest part of a steam system, this is where most of the dirt and "crud" collect. Here's an article from "Off the Wall" with tips on flushing wet returns which might be useful to you.

    - Rod
  • Breakthecycle2Breakthecycle2 Member Posts: 34

    ok, here is what I have. Where do I hook the hose up to flush the whole system. I am looking to just flush the water, not clean the boiler or anything.
  • Charlie from wmassCharlie from wmass Member Posts: 3,920
    Both, red for the return

    and grey for the boiler. Be prepared for either or both valves to be clogged and also to not shut back off once you do drain the system down.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Breakthecycle2Breakthecycle2 Member Posts: 34

    So what do I do if they wont trun back off?
  • 0409004090 Member Posts: 142
    If it doesn't shut?

    One novice to another, before starting get some brass caps that go onto a hose spigot, they will seal the end well. 

    I've had one on the hot water heater drain for years, and recently added one to an old boiler drain.  I can't see who posted to anticipate a leaky valve, but heed that advice and be prepared. 

    They look like a brass cup, come with a washer and work well.  You'll probably find them in one of those display plastic bags at the home store.
  • 0409004090 Member Posts: 142
    edited November 2011
    duplicated post

    Please delete, duplicated post
  • RodRod Posts: 2,067
    edited November 2011
    Hose Bib Cap

    Hi- Here's what the caps look like. You usually find the in the garden section (with garden hoses) of the big box stores. 

    If you have young children in the home, it's not a bad idea to use them as a safety backup to save inquiring hands from a bad burn!

    - Rod
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