Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

2 pipe vacuum steam - water in vent trap

Steamhead (in transit)
Steamhead (in transit) Member Posts: 6,688
in THE MAIN WALL
Cross-referencing to chapter 15 of "The Lost Art of Steam Heating", your "Thermoflex Alternator" is an Alternating Receiver which is a version of Boiler Return Trap. It helps the water get back into the boiler if the pressure rises so high that it won't return by gravity. It works with the two check valves in the photo. Make sure these checks are clean and that they operate properly. If they stick or get plugged, water will back up in the return.

I can't see from the photo- are there two pipes going into the Thermoflex Vent Trap? If so, it's also known as a Float Trap/Air Eliminator. It provides an air venting point- probably the only one in the system- and a float to close the vent if water backs up into it. The vacuum check is probably located on the top.

If there is only the one pipe going into this unit, it's just a main vent. In this case you'd replace the vent with a non-vacuum type. Also, check the ends of the steam mains for vents. These might take the form of radiator traps piped between the steam main and the dry return.

Thermoflex was the name used by the Grinnell Company for its line of steam traps. Until now I didn't know they made Vapor equipment, but there it is in very small print in the 1947 ASHVE Guide. I think this might be the same Grinnell company that is famous today in the industrial pipe fitting and fire-sprinkler fields.

The Vaporstat is a pressure cutout for the burner on the boiler. It stops the burner if the pressure gets too high. Normally systems like yours ran at less than 1 pound.

Vapor was the Cadillac of heating in its day, and is still one of the best out there. No "conversion" is needed other than to stop trying to run vacuum. Replacement innards are available for almost any radiator trap, and the Alternator could be rebuilt if it malfunctions. Technically the Alternator is not needed if you have a Vaporstat, but there's nothing wrong with keeping it- kind of like wearing a belt and suspenders at the same time.

<A HREF="http://www.heatinghelp.com/getListed.cfm?id=367&Step=30">To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"</A>

Comments

  • Ed_36
    Ed_36 Member Posts: 4
    Steam System - Water running over in the vent trap

    We have a 2 pipe vacuum steam system initially installed in the 1940s with a new Weil-McLain boiler installed in the past 5 years. The system has a trap on each radiator (no vents), 3 check valves, a vaporstat, a thermoflex alternator No. 0, and a vent trap. System will show 10-12 lb vacuum. When the boiler begins to generate steam and heats the radiators, shortly thereafter, water will begin to run/escape from the vent trap. We have found no blockage in the return line at the boiler, and the 3 check valves appear to be functioning properly. Looking for suggestions of steps to take to determine what is causing the water to build up at and escape from the vent trap.
  • Ed_36
    Ed_36 Member Posts: 4
    Steam System - Water running over in the vent trap

    We have a 2 pipe vacuum steam system initially installed in the 1940s with a new Weil-McLain boiler installed in the past 5 years. The system has a trap on each radiator (no vents), 3 check valves, a vaporstat, a thermoflex alternator No. 0, and a vent trap. System will show 10-12 lb vacuum. When the boiler begins to generate steam and heats the radiators, shortly thereafter, water will begin to run/escape from the vent trap. We have found no blockage in the return line at the boiler, and the 3 check valves appear to be functioning properly. Looking for suggestions of steps to take to determine what is causing the water to build up at and escape from the vent trap.
  • gerry gill
    gerry gill Member Posts: 3,078
    can you post pictures please.

    this will help alot.

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
    gwgillplumbingandheating.com
    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

  • Steamhead (in transit)
    Steamhead (in transit) Member Posts: 6,688
    On the vent trap

    there is probably a vacuum check at the air outlet. Remove this check and see if that solves the problem.

    Running at vacuum was great on coal, but not so good on oil or gas. This is one of the things that can go wrong.

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
  • Ed_36
    Ed_36 Member Posts: 4


    Thanks for your response. We are not clear on what you mean by the "vacuum check at the air outlet". Is this the the Thermoflex Vent trap? What is the function of the Alternator No. 0? What is the function of the Vaporstat? Would it be wise to convert the vacuum system to a pressure steam system, as this is a two pipe steam system? Would this require removing the steam trap cages at the radiators, installing steam vents on the radiators, removing the vaporstat, alternator and /or vent trap?
  • Ed_37
    Ed_37 Member Posts: 1
    Pictures of 2 pipe vacuum steam system

    Attached are four pictures for you to see.
  • Ed_36
    Ed_36 Member Posts: 4
    2 pipe vacuum steam - water in vent trap

    Yes, the system has two pipes going into the Alternator.

    Seems like the cause of the water going into the vent trap and not back to the boiler is either 1) the check valves not closing properly, or 2) the Alternator not functioning properly? In your experience, which would you tackle first?

    Is the alternator rebuild a difficult task? Are you aeware of firms that could rebuild the Alternator? We are in west of Boston by 30 miles? We could ship outside of Boston if required. Thanks again for your assistance.
This discussion has been closed.

Categories