Main Air Vent Location

JuanCHVAC

Hello. We are working in a 1928 hotel in Los Angeles, CA.  We are having issues with heating and steam going back to the boiler room.  
Its a single pipe system.  We already found a bad steam trap.  We went to the 6th floor and found theres no main air vent at the end of the suppy for the last set of radiators.
We punched a hole in the wall and found a 4 way fitting (see pictures attached).
Now my question is: can we remove the plug from the top of the 4 way fitting and install a main air vent and leave it behind the wall?  Or do we have to run it all the way up to the crawl space above the 6th floor.  Any well will be appreciated.

JuanCHVAC

Jamie Hall

You can put it there, but I'd put it up on a riser -- say about a foot -- in case there's any water in there.

I'd also put it behind an access panel, and make a note of where it is...

JuanCHVAC

Jamie Hall said:

You can put it there, but I'd put it up on a riser -- say about a foot -- in case there's any water in there. I'd also put it behind an access panel, and make a note of where it is...

Thanks.  I really appreciate your help. 

bburd

One pipe steam systems generally do not have steam traps. How many did you find, and where are they located?

JuanCHVAC

bburd said:

One pipe steam systems generally do not have steam traps. How many did you find, and where are they located?

Found these 3 coming from the returns on one side of the building.  I think someone put them there some time ago.  They are next to the boiler.  The 3" pipe coming from the wall is the return from the other side of the building.  Theres no steam trap there.
Also, thats where the steam is coming back from to the boiler room.  Im suspecting we have tons of risers with blocked/bad main air vents.  But thats just my guess. Pictures below

Steamhead

OK- there is a condensate return tank & pump there, which explains the traps. These traps are also supposed to act as air vents but often do not have enough air throughput to do this well.

Measure the length and diameter of your steam mains and we can tell you what you need.

Regarding the riser- do all your risers have vents except that one?

JuanCHVAC

Steamhead said:

OK- there is a condensate return tank & pump there, which explains the traps. These traps are also supposed to act as air vents but often do not have enough air throughput to do this well. Measure the length and diameter of your steam mains and we can tell you what you need. Regarding the riser- do all your risers have vents except that one?

I highly doubt thats the only blocked riser.  I already talked to the building management about inspecting all of them.

We are going back to that building next week and will keep you updated.