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Cold skim in off-season ok?

cubicacres Member Posts: 358
Any thoughts about trying a cold-skim in the off-season now that our boiler has been off for a few weeks and the new water temperature added won't shock with a temp. difference? We were thinking we'd just hit the water feed button until the skim tapping started to flow, then keep that going for a while and follow up with letting a few quarts out of the lower blow-off valves at each side of the bottom of the boiler to bring it back down to the sigh glass level & wipe the dirt out of the glass, along with some blow-off from the return side of the hartford loop where our wet returns begin with the valve we had installed at that location.
Ideally, using a wand might get more oil out, or a warm but not steaming boiler might make the oil a little less solidified? On the other hand, in colder water temp, the oil can rise more & tend to seperate from the water, right? The books all mention warm skimming (not when producing steam or no mention at all of when completely cold), but I'm wondering if that's because skimming is usually a response to surging or other problems that are noticed during the heating season?


  • BobC
    BobC Member Posts: 5,478
    Cold skimming helps but remember you should bring the boiler up to steam after your done to get the oxygen that the new water contains.

    If your going to have to fire the boiler anyway, you might as well do a cold and then a hot skim. You want to draw water off very slowly so any oils can just flow off the top surface of the water. You can add cold water to a boiler as long as it's done nice and slow.

    Just wait for a cool day, if your in NE the end of this week is supposed to be cool.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • cubicacres
    cubicacres Member Posts: 358
    Sounds good-thanks Bob.
  • ChrisJ
    ChrisJ Member Posts: 15,677
    Yes, make sure you boil the water real good after your done, keeping in mind any fresh water added to the returns needs to find it's way all the way into the boiler and get boiled as well.

    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • GreenGene
    GreenGene Member Posts: 290
    edited June 2016
    If I did it at all I'd do it once, oxygenated water is the enemy.

    A new install shouldn't need more than a skim, if you're cutting/threading pipe wipe it off, inside as well, gets as much oil off/out before screwing the pieces together, don't over dope into the fittings.