New Wet Return Line, Same Old Problem...solved!!

Jack_2

I figured out what the problem was. Apparently, the boiler must be thoroughly skimmed after installation of a new wet return line. Even though the piping was brand new, the oil residue and pipe threading material can contaminate the water causing the boiler to surge and throw water into the steam pipe thereby washing even more dirt and soot back to the boiler via the new return line. Don't go by the color of the water in the problem radiator or the gauge glass. This water can look deceptively clean while the boiler water itself can actually be very dirty. After several complete drains of the boiler and the wet return, I now have great steam and no more water hammer. Thanx again for all your ideas and help.



Following is previous message:
>I recently installed a new wet return line (same size as >old pipe) in a one-pipe steam system. This return line is >attached to a longer main (appx. 40 ft. long) of a 2 >header boiler (Weil-McClain). Just beyond where the wet >return is attached to this main, a new larger main air >vent was installed on a six inch nipple to hasten the >steam to the furthest radiator in the house. This worked >great for about 1 week. Then the old problem returned >where this radiator always seems to get flooded (with >resulting water hammer)intially when boiler is at start >cycle. I don't think this is condensate since the amount >of water escaping the air vent is fairly large. I also >noticed that steam and sometimes fresh colored water is >escaping from the new main vent after the boiler runs >about a half hour. The water level in the gauge glass is >appx. 1 inch from the bottom when the boiler is on. What >are the possibilties here? If the boiler is generating wet >steam (which is what I suspect) why would it work >perfectly for 1 week after the new wet line was installed? >Is it also possible that water from the wet return is >backing up in to the main line thereby pushing it into the >smaller branch to which the radiator is hooked up to? >Thanx in advance for your responses.