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Skimming a gas boiler .

misterheat
misterheat Member Posts: 158
in Strictly Steam
Does it make a difference if you skim a gas boiler after it is hot or does cold work the same ?? i have oil from a new radiator causing some bounce in my site glass while running .Thanks

Comments

  • BobC
    BobC Member Posts: 5,502
    I believe hot skimming is best but if the boiler is cold when I start, I start feeding water and skimming cold and run the boiler and skim it while it gets hot - nice and slow. Don't let it start to boil, you want the surface of the water calm so the oils can just flow out of the skim port.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
    misterheat
  • Abracadabra
    Abracadabra Member Posts: 1,948
    I prefer skimming while system is hot. Helps release oils from sticking to sides of pipes/boilers/etc and helps them float to the top.
    misterheat
  • MattRuocco2_2
    MattRuocco2_2 Member Posts: 2
    Can I cold skim a new boiler - 24 hours old? Contractor didn't do it and i'm comfortable doing a cold skim based on the instructions in another post. will that be good enough if i do it for the next 5 Saturdays or so?
  • BobC
    BobC Member Posts: 5,502
    It won't be as effective as a hot skim but it will get rid of the oils floating on the water. Once you have cold skimmed a few times perhaps you will be confident enough to try a hot skim, it's no harder but you do have to take care handling the hot water.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • MattRuocco2_2
    MattRuocco2_2 Member Posts: 2
    do you have a current link for how-to for a hot skim? i saw a previous post of yours and the link was expired. you're one reason why this site is essential.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,578
    What I did after the installation was completed, was to simmer a solution of washing soda in the boiler for an hour or so. Following that, I began a skim with the boiler off, and continued until all the soapy hot water had been slowly replaced by fresh cold water. Luckily, I had a selection of pipes to put the discharge directly into the floor drain, as lugging 50 gallons of water some distance would not have been fun.
    I did this 3 times in the first month.--NBC
    misterheatZman
  • BobC
    BobC Member Posts: 5,502
    This is a skimming article that I saved a while ago.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
    misterheat
  • MattRuocco2
    MattRuocco2 Member Posts: 8
    These are clear directions. Last question: at the end when I completely drain the boiler, do I use the blow down valve the plumber installed or do I use the garden hose type valve that came with the boiler?
  • BobC
    BobC Member Posts: 5,502
    The garden hose connection should be at the lowest point on the boiler so that is the one to use. When you go to refill the boiler, if it is still hot refill it very slowly so you don't shock the cast iron. Once it's back up to the normal level fire up the boiler and let it steam so you can drive off any oxygen in the fresh water.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
    misterheat

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