Master Trap

B. Norian

A contractor (with whom we have worked extensively in the past) called to describe a strange configuration (and problem). An ancient six-story office building in downtown Boston is heated with a two-pipe steam system. The terminal radiation is cast iron radiators, about two feet high, extending along most of the exterior walls. Because two of the floors were converted to hydronic with a dedicated boiler, we were asked to size a new (smaller) boiler. The contractor installed a Weil-McLain five section 88. During operation, no condensate is returned iniially, causing the auto feed to admit city water to the condensate receiver. Then a torrent of condensate comes back and floods the receiver. Here's the strange part. There are no traps on the radiation (two-pipe). the returns dump into a common loop that runs around the perimeter of the basement of the building, ultimately draining into a single 2" trap, which discharges to the condensate receiver. The system has been working for decades. How and why?

clammy

water loop seals

check the water level of the new boiler as compared to the old boiler what may have happen is the new boilers water line may be much lower then the original boiler which in some cases may make you lose the water seal between each condensate drop and because you have stated that the rads do not have traps then what pervents the steam from entering the return lines , when steam enters the dry or drip return drops it stops the pressure differental and also stops steam distrubition.I would check your boiler water line and see if that horizontal return line is well below the boilers water line if not then you could either install water seals on each drop or rads traps on each drop or fabracatea false water line in the boiler room and put all those drops back under water so steam does not reach them .if this is a gravity condensate return system then you could also get rid of that master trap and return the system back to it's original design .also check what your pressuretroll is set at .05 cut in 1.5 cut out .Are there any main air vents or crossover traps on this system 'hope this helps you peace and good luck clammy