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steam radiator heating up by air vent first

I have a single pipe steam system.  There is 1 old (not thin wall/never for hot water) radiator that recently began to heat up at the air vent side first.  I have had steam heat for 8 years now and have played with it a lot and all of my radiators begin getting warm at the valve and the last fin to get warm is the one with the air vent.   With it getting warm at the air vent first I am wondering if perhaps there is a clog in it?  Should I maybe see about flushing it?  Since this will be a beast to move  (It is 42" high, 4 wide tubes and 10 fins long) and I don't want to wrestle with it too much and was hoping someone else has seen this and has an idea of what is going on.



Thank you!

Comments

  • Dave in QCA
    Dave in QCA Member Posts: 1,785
    Radiators seldom get clogs

    Actually, there almost never get clogs, I have never heard of a clogged radiator.  But, lots of other problems can make one thing that there is a clog.  Please take a picture or the radiator.  Make sure that we can see the inlet and the vent end of the radiator.  That will help.
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
    http://grandviewdavenport.com
  • Dave in QCA
    Dave in QCA Member Posts: 1,785
    edited December 2012
    duplicate post-please delete

    .
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
    http://grandviewdavenport.com
  • Steamhead
    Steamhead Member Posts: 16,796
    The steam

    is probably shooting across the bottom of the radiator and then up to the vent. Try slowing the venting rate and see if this helps. 
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • mattoon
    mattoon Member Posts: 3
    switched vents

    I had been using a hoffman vent that was really slow.  I switched it to a variable one and barely open to wide open, the radiator valve gets hot first, then the fin by the air vent, and it slowly works its way backwards.  Two fins in the center actually stay cold and then both ends are warm.  I will try to get my camera working tonight and post some pictures later.
  • Dave in QCA
    Dave in QCA Member Posts: 1,785
    FAST VENT

    That behavior would seem to indicate that the setting of the vent is to fast for the radiator.  If the steam shoots straight to the vent, it will close and you still have a radiator full of air.  Of course it will open up again, but you will get better results with a slower setting.  Is this a Heat Timer Varivalve by any chance?  Those are as fast as many main vents.
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
    http://grandviewdavenport.com
  • mattoon
    mattoon Member Posts: 3
    will try a slower vent

    I will switch back to the old hoffman--that was on it for two years and the radiator behaved normal.  I confess that although it is a slow vent, they do not clog like the maid-o-mist that I can find at Lowes.



    I tried taking a picture that shows front and back  (and yes, it is painted flat black).
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
    That looks like a Durst or USAV

    not a Maid-O-Mist. I bet a MOM #4 would be just right.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
This discussion has been closed.