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Steam Radiator problem

RFlynn Member Posts: 2
I have been trying to figure out why a steam radiator at the end of the line is not working even when the riser is getting hot on the radiator itself.  I have taken out the vent and it still does not heat up.  It seems to be taking all the heat to the radiator about 5 feet away but does not get to the one at the end of the line.

Should I try and put a vent at the end of the line so the steam to get there quicker?

Not sure what the problem is, pelase help.




  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,576
    cold radiator

    i am presuming this is a 1-pipoe steam system, since you mention a vent. with the vent removed, steam should be coming out of the tapping, if there is no obstruction.

    if the pipe up to the radiator gets hot, then the blockage must be in the radiator somewhere. is it pitched down slightly towards the valve? is the valve fully open? the bonnet of the valve can be unscrewed to check for a fallen disk on the valve stem.--nbc
  • JStar
    JStar Member Posts: 2,752

    You may also have very wet steam that will bog down the steam before it can get to the radiator.

    Any pictures of the boiler piping and radiator piping on the main?.
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,849
    It could be a lot of things.

    In addition to what NBC and JStar have said, it might be the case that your boiler is undersized and the steam just plain peters out before it gets to the last radiator. But we'd need a lot more information about your system, like the model of your boiler, number and sizes of radiators, insulation/no insulation on mains, type and location of vents, and some pictures of the boiler and piping would be helpful.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • Dave in QCA
    Dave in QCA Member Posts: 1,785
    Perhaps an over-venting problem

    I agree with all possibilities that have been offered, but will add this one to the list.

    First, can you tell us, assuming that this is a one-pipe system, what types of vents are you running on the radiators and what type of main vents?  I have seen a system do exactly what yours is doing and the only problem was that the radiators were being vented way to fast.  As a result, the last radiators never got steam until after an hour of boiler operation, and the house was burning hot, all except the room with the last radiator, which is also where the thermosat was located.  Ugh!   Slow radiator vents, combined with decent main venting made it run like a charm.
    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.
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