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Sunrad Radiator - Loud banging problem

RonW Member Posts: 2

I have a 13.5" Burnham steam Radiant Radiator that bang loudly whenever it starts to heat up. I assume it's because the pipe is not pitched. I don't have a level small enough to fit in the area of the pipe, but I measured the pipe from the floor in 2 spots and there is no pitch. It's a single pipe system.

Based on the attached photos, can you tell if there is an issue with the way it is piped? If that's not the issue, any suggestions to stop the loud banging?




  • BobC
    BobC Member Posts: 5,309
    Is the floor level?

    If it is level i would expect some noise but I would not expect the anvil chorus unless it's pitched the wrong way. Is the floor it sits on level?

    Is there a length of horizontal pipe under the floor that might be pitched wrong?

    What kind of air vent is on the radiator? If it's venting at too high a rate rthat could make the problem worse.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • KC_Jones
    KC_Jones Member Posts: 5,082
    Pipe Size?

    Could the pipe size be an issue?  I know you need a certain size pipe for a certain amount of EDR and counter flow.  There is a chart in one of Dan's books on this, don't have them in front of me or I would look it up.  It's hard to tell for sure in the picture, but that looks like 1/2" or 3/4" copper.  Could also depend on the pipe size under the floor.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • RonW
    RonW Member Posts: 2
    more info...

    The floor is level and the unit itself is level. There's no manufacturer listed on the vent, is there something specific about it I can describe to you?

    Also, the pipe is 3/4 above the floor, don't know what's below it.

    This is a 2 family house, both with the same radiator in the bathrooms and both of them sound like someone's banging the anvil when it starts to heat up.

    So how much pitch should there be? should just the pipe be pitched or the whole unit?

    Thanks for your help!

  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,564
    anvil chorus

    For that size rad, I would think that at least a 1 inch pipe, is needed, to allow room for condensate and steam. possibly, the copper pipe is lengthening as steam fills it, reversing its pitch [another reason copper should be never used for steam lines].

    A cure may be to re-pipe in steel 1,1/4 pipe, or to pipe a return drain, back down to the wet return. from the end of the Sunrad.--NBC
  • KC_Jones
    KC_Jones Member Posts: 5,082
    Pipe size

    Do the rating charts even go down to 3/4" pipe?  If memory serves the slope should be 1" in 10' for counter flow.  Also the radiator itself should be sloped towards the connection to aid in flow of condensate.  Something else I just noticed...in the larger picture of the radiator is that vent on the same side as the connection?  It's hard to tell in the picture if that's a vent or something else.  The vent should be on the opposite side from the steam connection.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • JStar
    JStar Member Posts: 2,752

    We have a rule in our company...If you want to find the problem (in a steam system), follow the copper first. Chances are that the knuckleheads who used the copper piping didn't install it correctly.
  • Dave in QCA
    Dave in QCA Member Posts: 1,776
    edited May 2014
    Pipe Size is the Problem

    Pretty sure that it is the supply pipe that is causing the problem.  When steam is first going into a cold radiator, there is a huge amount of condensate flowing back out, and the steam and condensate will hammer up a storm if they cant get past each other.

    Here are the size ratings from TLAOSH

    1" inlet  20 EDR Max

    1.25"    55 EDR Max

    1.5"      81 EDR Max

    2"        165 EDR Max

    As you can see, there is no size where 3/4 pipe is specified.  It's just too small for 1-pipe steam.

    Also, the air vent on the rad should be no higher than the middle of the rad.  Yours is in a port that is intended for hot water use.  Those screw plugs a little more than have way down are where the steam vent goes.  And, the vent should be on the opposite end as the steam inlet.
    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.