Two Pipe System

I have a 2 pipe system with the rear and front of house have there own feed an returns.Upon checking system found some one had raised pressure up to 8 and cut out at 11 thinking it would help get heaT to radiators. This system is for the second floor only of a 2 story house. Needless to say all the traps failed in the closed position. I cant see the front of the house because it is all sheetrocked but in the rear I see a 1" steam main that goes up and along the ceiling for about 8" than goes up into the sheet rock. right next to it a 1" return line comes down thru sheetrock runs across and drops into a wet return. which also picks up front of house. It than goes into a Hartford Loop and back into boiler. I lowered the pressure so that the boiler operates between 1/2#and 1 1/2# . The boiler now builds pressure right awaay and shuts down beacuse the steam has no place to go because the traps have failed. This is a new system and I believe it has been piped wrong. . I want to make sure just how it should be piped . There is no F&T trap anywhere here and I believe it is required as well as a vent on the dry return. Any help would be appreciated