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Annual Brief Cold Skim Early in Heating Season Good or Bad?

Just curious about some opinions on a practice we've gotten into the habit of doing the last few years, and are a bit late in doing this year since we haven't done it yet...

After a month or so of running our WMC EG-75 single-pipe steam boiler each fall/early winter, we've used the Safeguard fill switch to slowly add a few gallons of water from the usual operating water line on a warmer day (when the boiler hasn't run for several hours to minimize shocking of the metal with new 50F temp city water) up to the skim port level for a several minute skim of another gallon or two to remove any surface particles from the boiler water that may have accumulated via condensate lines (mostly dry condensate until returns drop below water line back in boiler room right next to our boiler) after running the first several weeks each season. We then lower the water level via the 2 valves on the bottom of each side of the boiler (blow-down style like we used to do with the old boiler which required it more often per our understanding, since our new boiler has a probe & no weekly/monthly blow-down ritual) & add 1 steammaster tablet (heard best to use them sparingly & one at a time as needed) if the water has lost the pink color inside the gauge glass.

In spring before shutting off the boiler for the season, we add 1 steammaster tablet if the pink color has faded from the water over the winter heating season & run it for 20 minutes to dissolve it before filling up the water line just over the top of the sight glass & at slightly different hights each year to avoid the same water line rust line inside the boiler that might occur over the non-heating seasons until we start it up again in the fall.

Is there any benefit to doing this annual skim to try and remove surface dirt on the water line inside the boiler via the skim port each season, or is introducing a few gallons of water not worth it?


    EBEBRATT-Ed Member Posts: 15,346
    I see no harm in what you are doing.

    In addition if it was me I would drain and flush the boiler once a year in the spring or fall. While it is drained I would clean the gauge glass, pigtail, pressure control and low water cutoff. Put it all back together fill it up put the steam master in and run it so it steams for a while to boil out any oxygen and shut it down