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Steam radiator Frankenstein

jmet
jmet Member Posts: 15
So per usual steam radiators were chopped. Removed. “Fixed” etc over the years. What was once a two pipe system is now a one pipe. Although there is a return line for the second floor radiator that remains. Heres the issue im having.. on the second level the radiator has a 3/4 brass steam valve and a 90 degree elbow return, also a air vent.  Hmmm. From what I understand the two pipe radiator should not have an air vent ,right? If not what woul i put in its place? As far as the elbow goes. I was told to replace with a f&t trap… but also a vacuum breaker???? Adding a picture below. Let me know what would work best?

Comments

  • mattmia2
    mattmia2 Member Posts: 9,631
    Can you post some pictures of the other radiators? How are they set up? Where does that return go? It is possible to have 2 pipe steam without a trap if you have a metering valve or an orifice plate and control the pressure so that only the amount of steam that the radiator can condense enters the radiator.

  • Jamie Hall
    Jamie Hall Member Posts: 23,276
    Before full two pipe systems with traps etc. were developed, there were two pipe steam systems which were set up in much the way you have pictured. Are there any other radiators set up that way in the building? If the building -- or even this one radiator -- is set up that way, and it works, there's no need two change anything. Systems of this type are described in "The Lost Art of Steam Heating", available from this site.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
    Connecting a drip to a one-pipe radiator, for whatever reason, doesn't make it two-pipe. Two-pipe systems allow the air to escape through the second pipe. If that's just a drip to allow the condensate to flow out without interfering with the incoming steam, it should go straight to the wet return and should never see significant steam. It it's neither, it's a problem. Either way, you need a vent to let the air out, but it should be much lower than it is now.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • jmet
    jmet Member Posts: 15
    Connecting a drip to a one-pipe radiator, for whatever reason, doesn't make it two-pipe. Two-pipe systems allow the air to escape through the second pipe. If that's just a drip to allow the condensate to flow out without interfering with the incoming steam, it should go straight to the wet return and should never see significant steam. It it's neither, it's a problem. Either way, you need a vent to let the air out, but it should be much lower than it is now.
    Maybe the wrong radiator? There were a few damaged ones that were replaced. That line goes directly to the wet return/hartford loop. The issue of the steam system is intense knocking and gurgling. Mainly that one radiator. The other 5 are 3/4 valve and have1/8” quickvent. The system was bled last year. Had the main vent replaced amongst enlarging the diameter of the longest run (so the steam can “pass” over the condensation. Seems to have worked for a while. But back to the good ol knocking 
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
    Maybe slowing down the radiator venting will help. When air or steam passes over water, it causes waves to form. The faster the flow, the higher the waves. When a wave peak reaches the top of the pipe, it forms a slug, which then gets hurled against the end of the pipe with great force. This type of steam hammer is called differential shock. It can be very destructive.

    https://www.youtube.com/watch?v=JyvoN1hIqRo
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • jmet
    jmet Member Posts: 15
    mattmia2 said:
    Can you post some pictures of the other radiators? How are they set up? Where does that return go? It is possible to have 2 pipe steam without a trap if you have a metering valve or an orifice plate and control the pressure so that only the amount of steam that the radiator can condense enters the radiator.
    All the others are tilting back towards the valve i also had someone suggest its all due to lack of insulation on pipes.. after asbestos remediation they were never insulated (coming up this week) pics to follow
  • jmet
    jmet Member Posts: 15
    just noticed the radiator lines that are pitching back to the main line seem to be slightly lower than the headers. Does this piping seem right? I would think all returns go to the hartford loop. Only one radiator is piped to the return. All others to the main. 
  • jmet
    jmet Member Posts: 15
    Also.. check that main line vent situation 😂
  • mattmia2
    mattmia2 Member Posts: 9,631
    That particular radiator should probably be pitched toward the return. Steam shouldn't really be able to get in to that return as long as is goes in to a wet return and the water line is high enough above the return so that the steam can't push the water out of the return. Lower pressure at the boiler is better. If the boiler was replaced and the water level is now lower than that drip was designed for you will have a problem.
  • mattmia2
    mattmia2 Member Posts: 9,631
    The runouts have to pitch back to the main so that in the case of the one pipe radiators the condensate from the radiators can run back to the main and in the case of the 2 pipe radiator any condensation in the runout itself can run back to the main.