C hanges to Bromell system i am not clear on

mstrbill

To be short , Bromell system was changed when new boiler was installed . They changed all the outlets on rads to thermostatic , replaced receiver with a Hoffman 15 T & P , back in boiler room for what reason i do not no because its on dry return. They took out floor convectors and at each one they joined the dry return with they wet return underneath it but used Traps and kept the check valves in line . the traps were on the dry return side. I wonder what they were doing there, no problem , just what are they doing ?? my questions are the trap in the boiler room , ? dont need it ? drip is good height and i keep pressure low now with vaporstat, they had it at 5 psi. and what are they return bypass pipes for from wet to dry ???

Thanks for reading.