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The Banging is Back

mchema Member Posts: 37
I finally fixed my banging rad.  For one solid month I have been enjoy quiet sleep proof nights but one early morning I was awoken to an all too familiar sound, the banging of the bathroom rad.

The last fix was a bit of a run around. I thought it was the rad in the adjacent room but after a couple weeks of messing around with things I gave the bathroom rad a try b/c sound can carry weird. I just put some quarters under the end opposite the valve and piece and quiet...

I did notice that the pipe coming out of the floor was leaning towards the rad a lot (that's what gave the the idea that may be this was the rad with the issue, even though the rad was pitched correctly). When I stuck some quarters under the rad it seemed to help straightened the pipe out a bit.

So I put one more quarter under each leg last night in hopes it would work but no... I don't want to tilt the rad much more. There is a lot of give left to right with the pipe. I'm thinking when I "fixed" it the first time I shifted the piped in a better position but as the month has gone on with all the expansion and contraction is has settled back into place. Anything other thing I can try since I do have wiggle room...?


  • Shimming

    Well at least you now know which radiator is causing the noise.  I'd would just play around with the shimming adjustment of the radiator. Keep in mind it is possible to shim one end too much. If the radiator has too much slope, you get all the condensate (water) immediately rushing into the pipe and this can cause a problem. 

    You might try and see if you can raise the whole radiator. There is usually a bit of slack in the piping and you might be able to raise it a bit and then then shim evenly under all of the four of the feet. When you have the radiator settled properly add the normal amount of shimming to slope it toward the intake pipe.  Raising and shimming are easy to do if you use a short length of 2x4  and blocks as a lever. This is is a two person job with one lifting and the other steadying the radiator and shimming. I'd also recommend you check the radiator's slope with a carpenter/s bubble level. I had one big radiator that I shimmed till it had plainly visible slope but it still hammered. I finally figured out the floor had sagged and the radiator needed far more than normal shimming.

    - Rod
    1PIPERADS Member Posts: 3
    adjust valve side?

    I agree with Rod, try adjusting (lifting) a bit on the side of the valve, that part usually gets forgoten, then make sure the (valve side) is pitched toward the valve.
  • mchema
    mchema Member Posts: 37
    Will Try

    That was my next step. Plus the rad at that end had kind of stuck itself to the horrible peel-in-stick floor. so when I use my lever the one side stay put, haha. That area is a sagging floor area. Has anyone had their floors corrected with their steam heat? Meaning...

    In the spring after we turn down the system we have to put up a support beam in the back half of our home, there is too wide of a span and over they years a sag on the first floor has become evident. There are a couple things that worry me. 1) The contractor has to take off the mains 2) the mains have to rerouted before they put the beam up and do some floor jacking (leveling out the sag)?. Anyone ever have this kind of experience? And if so how did your steam system work the same after they put it all back together again? The plumber my contractor works with works with cast iron and all that jazz but should I be bringing a steam specialist in? are there any questions I should be asking before I let this guy have at it other than his experience and such..
  • jacking up floor

    i would suggest that you plan the route now the new pipe will take after the new beam is in, so as to get the proper slope from end to point of connection. a water-level might be useful here, if the area is broken up by walls, etc. if the pipe needs to cross the beam, it must go over, and under the beam, for drainage.

    the new pipe could be put in, and before it is connected to the radiator, or the main, it could be tested for drainage, by pouring a certain amount of water in at the rad end. naturally, the same amount should come out at the downstream end.

    if this is a counterflow system, consider putting some vents at the end.--nbc 
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