2 pipe steam system getting air bound

lostinheating

Good evening. This is taking place is a 21 story building with a 2 pipe steam system. At the very top of c kitchen line there was once a radiator with an air bleeder on it. The radiator has been removed and supply and return capped. Found out few people in only that line weren't getting heat. Went to coil below where its capped (20th floor) replaced then removed trap element and still not getting heat. Put a Gorton air valve on it and worked great,only problem was spitting out condensation. We have a new vacuum systems well. I plan to put a vac gauge up top just to see what it's pulling. As of now the air valve has been removed and plugged. So no heat.
Should I just hook supply to return up top if there's access? Don't want to add love steam to return line. What doesn't make sense is how come even without a trap element the coil below is still getting air bound.

Jamie Hall

Hard to say on the coil -- but the solution to the line at the top is straightforward -- add a crossover trap from the top of the steam riser to the return. That will allow air to escape (quite quickly -- a crossover trap is equivalent to a pretty good size vent) -- but not let steam get into the return.

What pressure are you running the boiler at? It probably doesn't have to be over 2 pounds.

lostinheating

Thx for Input. System runs to max which is 5 psi.