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Please walk me through how to skim my boiler (WET STEAM) = PICTURES INCLUDED.

tumbz Member Posts: 94
Guys, im back. THis is the first time im going to try to skim my boiler. I have an idea on how to do it and i am confident that i can, but can someone please walk me through it step by step. This is my first time and im a total newbie. I hear some banging in the radiator closest to the boiler and im suspecting WET STEAM. It has also been quite a few years since it was skimmed.

I understand that the manual shut off should be partially opened with the hose attached and the boiler semi hot.

Here are pictures of my boiler on both sides. Please tell me which valve i should use to attach the hose to or any other parts i need to buy to make this work.

Please walk me through step by step.



  • tumbz
    tumbz Member Posts: 94
    you guys see the relief valve on top with the yellow handle? Can i just unscrew the relief valve where the T is and just skim that way? Take off relief valve and unscrew the end and connect a hose to it. Run boiler till its almost steaming and shut off and partially open the manual water in?

    Can anyone give me step by step instructions?

    Everywhere i read is only HALF **** instructions. Please walk me through it so i dont make a mistake my first time.

  • acwagner
    acwagner Member Posts: 505
    edited October 2019
    I have a similar boiler. I'm sure everyone does it slightly different, but this is what I do.

    First, turn the boiler on for a few minutes. You want to warm the water up, but not to the point it's boiling. Then, turn off the boiler so it doesn't start up on you while you're skimming. When you add the new water, it will be cold and stay at the bottom of the boiler. All the warm/hot water will be at the top with the oils on it so you can remove it. Firing the boiler also suspends most of the sediment that's in there, so it's easier to remove.

    In your case, someone thought ahead and made it easy. You don't need to remove the PRV. Just unscrew that cap at the end of the pipe and open the ball valve.

    Then, turn on your water and slowly fill up the boiler until water starts to trickle out of the open pipe.

    I prefer to catch the water in a bucket so I can see what's coming out and see the progress, but you can use a hose to. If you use a hose, you'll need to buy a fitting to screw onto the pipe to convert from pipe thread to a hose thread.

    Leave the water on so it continues to trickle out. Over time the water will change color from dark to light to clear. Once it's clear, you're probably good. Might take an hour or two for that to happen depending on how big your boiler is and the flow rate, etc. Maybe longer. Maybe less.

    Turn off the water. Then put humpty-dumpty back together again.

    After, drain the water back down to recommended water level for your boiler.

    Then, immediately fire the boiler with the new water. This drives out some of the gases that cause corrosion. Fire at least long enough to start making steam, but it's recommended to do it long enough to boil most of the water. That might be 20-30 minutes.
    Burnham IN5PVNI Boiler, Single Pipe with 290 EDR
    18 Ounce per Square Inch Gauge
    Time Delay Relay in Series with Thermostat
    Operating Pressure 0.3-0.5 Ounce per Square Inch

  • tumbz
    tumbz Member Posts: 94
  • Fred
    Fred Member Posts: 8,542
    That's a Burnham boiler. I have a Burnham also. They are super sensitive to any oils in the water. The instructions that @acwagner provided are correct, however, because the skim port is only 3/4" (the PRV port) and you must skim very, very slowly or you are wasting your time. Once you fill the boiler up, until water starts to trickle out of that port, make sure it is just a trickle. I do use a hose and I run it over to a floor drain and I let it trickle over night. (adjust the water supply down until water just dribbles out of the skim port and then hook your hose up to the pipe. You don't need a hose adaptor because that pipe is 3/4", the same size as the hose and the trickle is so slow that water won't leak at that connection. Overnight may seem like a long time but, trust me, with a 3/4" port, the slower the better. You want the water in the boiler to remain very calm so that the oils float off of the surface and out the hose.
  • JohnNY
    JohnNY Member Posts: 3,231
    First, take the jacket off and find the plugged skim port.
    Next, remove the plug. Then install a nipple and full port skim valve. Then put the jacket back on. When you get that done, check back in.
    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
    Consulting & Troubleshooting
    Heating in NYC or NJ.
  • tumbz
    tumbz Member Posts: 94
    @Fred ty fred. I will do it this coming week.
  • pecmsg
    pecmsg Member Posts: 4,880
    Any pics of the supply piping?