MAIN VENTS

jhansen

I walked into a boiler room this morning of a single pipe steam system not working properly. Installed by others so I went through the whole system. There are two steam branches off the header and only one is heating. What I noticed is that where two dry returns come into the boiler room and originally dropped into a wet return individually at the floor they were re piped so they connected up in the air. Although they both had main vents on them only the one on the working side would vent air. Is this because by tying them together up in the air they fight each other to vent properly. They now basically dead head into each other. Any help would be appreciated.