Condensate line 2 pipe steam

richarddowling

When I remove cover on trap and remove insert, I see water and there are air bubbles blowing up to surface. Water drains, but why the air? Is this normal?

EBEBRATT-Ed

Downstream of the steam trap you need air vents to let the air out of the system. I suspect you do not have vents or they are not working. The only exception to this would be if the returns go back to a vented condensate pump.

The return lines should be pitched down away from the trap so the water returns to the boiler.

If you pour water into the trap with the cap removed the water should drain back to the boiler. The air bubbles you see is the water displacing the air in the return line. Since there are no vents the air bubbles back up into the trap

Pumpguy

To elaborate on @EBEBRATT-Ed's post, I would look for a water seal in the return line(s).

If the returns are not piped for full gravity drain as originally designed, you could end up with a water trap, which will need upstream air pressure do displace.

A classic example would be uphill piping to the inlet of a condensate pump's receiving tank.

richarddowling

I think I will replace the Gorton air vent on the main line. I'll have to check and see if it is working when boiler is running.

nicholas bonham-carter

Are there crossover traps in this system, and have they failed shut?--NBC

richarddowling

Not sure. Where would they be located?

Jamie Hall

richarddowling said:

Not sure. Where would they be located?

Crossover traps are at the ends of the steam mains, above the mains, and piped over to the adjacent dry returns. They usually look like -- and are -- the same as the radiator traps.