Skimming port

Atmospheric steam boilers are very susceptible to corrosion cause by the oxygen in added fresh water. Keep careful note of any water that has to be added to the boiler. If water has to be added more than once a month it's important to find and fix any leaks in the system. Too much fresh water shortens the life of boilers. Make sure you make steam right after adding fresh water to drive off any oxygen.

After you install a skim port and skim the boiler you should consider adding something to raise the PH of the water to about 9 to forestall corrosion in the boiler and keep a watch on any water you have to add.

Bob

You want the boiler water to be hot but not boiling. I usually let my boiler run through a heating cycle and then shut the power off so that it can't come back on. After I am sure there is no more steam in the system, I then remove the pressure relief valve and elbow and connect a 6" nipple with a full port shut off valve on the end of it so I can close it if necessary. Slowly fill the boiler with water (using your regular manual feed) until the water starts to trickle out of that port you installed. Adjust you supply water down. You want to let it trickle very slowly (some suggest a stream no larger than the diameter of a pencil) I find i get the best results with an even slower trickle (as slow as you can go while maintaining a steady stream). This keeps turbulance inside the boiler to a minimum so that the oils stay on the surface of the water and flow out. Once I get the trickle the way I want it, I attach a garden hose to the end of the ball valve and run it to a floor drain. Because the trickle is so slow, it will take a while for you to see any water running out of the hose but be patient. I usually let mine run that way for 5 to 6 hours. If it's not to cold outside, I may even let it run through the night that way and put things back together when I get up the next morning. After you have the pressure relief valve back on, lower the water in the boiler back down to its normal level and fire the boiler up to allow it to burn off the excess oxygen from the fresh water in the boiler.The idea, when skimming, is for the water to be hot and you'll be surprised that it will still be warm in the morning.