Welcome! Here are some tips for using this forum.
I recently did some re-piping of a steam system. The whole system was one pipe convectors originally. Someone added an addition to the house and put two convectors that are two pipe with traps on them. We ran the return from the the main that feeds that section of the house and the return from the two convectors independently to the wet return instead of putting a trap at the end of the main and we have a Gorton number one on each of them. I expected this to work and to simplify things by getting rid of a trap. The vent at the end of that main starts spitting after about 20 minutes. I think it needs to be skimmed more but want to make sure I'm not missing something. We have already done a lot of skimming and it hasn't helped I have attached a drawing of the system.