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Wheres the trap?

Can this Steam convector rad. be part of a two pipe vapor system?

The rads all have 2 pipes and no visible traps,and no vents.I have never seen one.Is it a Trane convector?

Where can I get more info?


  • Steamhead
    Steamhead Member Posts: 16,823
    There are two possibilities........

    1- the installer mounted the traps or vents in the return runouts under the floor (in the ceiling of the basement) instead of in the convector cabinets, or

    2- there are no traps, the vent is on the dry return, and this is an Orifice Vapor system.

    First check the basement ceiling. If the convectors discharge into a DRY return, it's almost certainly Vapor. Check for traps in the return runouts from the convectors to the dry returns. If there are none, it's an Orifice system. Go out and get a Vaporstat, you'll need it. And make sure the dry returns are well vented.

    If all the convector returns drop into a WET return, look for an air vent in the return line from each one. In this case, there would be no other way for the air to vent. This setup might sound farfetched, but there is at least one group of houses in Baltimore where all the steam systems were installed this way.

    And take some pics while you're there!
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • ok

    Thanks, this is an Orifice Vapor system.main vents on the end of dry returns.
This discussion has been closed.