On a two-pipe steam system, if steam is coming out of the vent on the condensate return tank, what is likely the issue?

On a two-pipe steam system, if steam is coming out of the vent on the condensate return tank, what is likely the issue?

• A. Faulty steam trap somewhere
• B. Leaky vent
• C. Overpressure
• D. Blocked condensate line

Answer: (A)

In a two-pipe steam system, traps at radiators are meant to let condensate drain back while blocking live steam from entering the condensate return line. If steam is coming out of the vent on the condensate return tank, it means live steam is bypassing the condensate traps and reaching the return line up to the tank. The most likely cause is a faulty steam trap somewhere in the system that is not closing properly or is stuck open, letting steam pass into the condensate line and out the vent. A leaky vent wouldn’t by itself explain steam in the return line; overpressure would show up in other components too, and a blocked condensate line would cause condensate backup or water hammer rather than steam appearing at the return vent.

In a two-pipe steam system, traps at radiators are meant to let condensate drain back while blocking live steam from entering the condensate return line. If steam is coming out of the vent on the condensate return tank, it means live steam is bypassing the condensate traps and reaching the return line up to the tank. The most likely cause is a faulty steam trap somewhere in the system that is not closing properly or is stuck open, letting steam pass into the condensate line and out the vent.

A leaky vent wouldn’t by itself explain steam in the return line; overpressure would show up in other components too, and a blocked condensate line would cause condensate backup or water hammer rather than steam appearing at the return vent.