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How do you clean a sooted gas boiler with water?

Joseph_4 Member Posts: 271
Hello out there,

 I need some advice. I spent the better part or a rare Sunday off cleaning a boiler whose nipples are too close to get my boiler brushes in well. It seems to have sooted up cause of heavy construction dust. After cleaning. flame is still rolling out.

I never had to do the water method, but it seems I have no choice here.

 The customer has no heat or hot water ( its a domestic coil boiler). and has a bunch of small children.

any method to then dry out combustion chamber/refractory

how long to fire up and dry out before putting back in operation

Any help would be greatly appreciated. I need to know what works


Joe Hardoon


  • RJ_4
    RJ_4 Member Posts: 484

    Are you talking about a boiler heat exchange coil like a Raypak or Teledyne Larrs ?

    I would lay down lots of plastic sheeting. its going to get messy.  I than would use a large shop vac and CO2, or compressed air.  I have a large CO2 bottle with a 5 ft by1/2 inch i.d. hose open on 1 end i use.   Be careful using CO2 indoors and in closed areas as it can deplete oxygen levels.  You will get dirty, where a Tyvex suit and a good particulate mask.
  • heatpro02920
    heatpro02920 Member Posts: 991
    edited March 2013
    get a smaller brush...

    I never had one I couldnt get a brush through, but I have some tiny brushes, for the really tight ones I use rope and wire, feed the wire through with the rope connected then toggle through the he with the rope, the compressor blowing and the vacuum sucking...

    For water I use my goodman coil pro, but this is rare, normally vac, air, brushes, rope will get the job done...

    Are you sure the boiler is rolling out because its clogged, did you check draft before and after HE? WHats the temp in the boiler room, I have had cold boilers that wouldn't run until the chimney was warm and the boiler was over 60*.. Buderus g115 drove me crazy for almost an hour, until I figured out the water in the boiler wsa down to 40* {in a garage} and the chimney was hardly pulling, I put a blow drier in the burner opening for a while, plugged the burner back in and it ran perfect...
  • unclejohn
    unclejohn Member Posts: 1,833
    Pull The

    Burners and cover the electrics with a plastic bag and go to town. Ans away go troubles down the drain.
  • TonyS
    TonyS Member Posts: 849
    Water cleaning a boiler

    I often will clean oil boilers with water, I haven't run into a gas boiler yet, but no reason it shouldn't work.

    First off we are talking cast iron boilers. Second, I really prefer if it is a rear flue boiler or the cleaning port is on the side.

    Open up the cleaning port on top of the boiler with the flue still connected and run the boiler up to 160 minimum. Turn your aquastat up to 220 so the system keeps running.

    Next you use a spray bottle, like a Windex bottle or better yet a sprayer that you pump up, often used for cleaning ac coils,

    After the boilers at about 160 start spraying down into the sections, don't over spray.

    You will see the carbon just flak off and go up the chimney, you will also be able to see the water turn to steam long before it makes it down the section. If you see the water dripping off the section into the firebox you are spraying too much.

    When your finished the boiler will look brand new.

    With gas you may be able to do it with a top vent pipe removed if you keep a CO alarm nearby and all the basement door open with a fan. Cant say for sure.
  • Tim McElwain
    Tim McElwain Member Posts: 4,608
    Get yourself so old roast pans

    remove the burners and the gas manifold. Place the pans underneath the sections. use a soot sword and small brushes (brushes used to clean the barrels on rifles are great) with a soot vac to get the big stuff. Then get a spray bottle and do a 50/50 mix of water and a strong industrial detergent like industrial 409. Spray down into the sections letting it collect in the roast pans. Dump the pans, put them back under the sections and mix a 50/50 mix of hot water and white vinegar in a spray bottle and spray sections allowing to run down into the pans. Remove pans hook everything up but leave sections open and get the boiler hot over 180 degrees. shut the boiler off and spray water vinegar again it should hit sections and dry right up. Now seal everything up and fire away, Conduct a combustion analysis and monitor CO closely, it should be well under 100 PPM.

    Keep the roast pans for the next cleaning. I have cleaned hundreds of gas boilers this way it works great.
  • Joseph_4
    Joseph_4 Member Posts: 271
    Thanks for the input

    Thanks for all your input.. I removed mainifold. lined with pans and used Garden hose with spray gun. Took hours. What a messy job. But boiler is clean and they are up and running. Can't say I'd be ready to do another cleaning job tommorow!

  • unclejohn
    unclejohn Member Posts: 1,833
    This sounds

    Like a good idea and a lot less messy then mine.
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