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One problem results in another

My largest (one-pipe column) radiator was producing solid water hammer or two at the beginning of the cycle, so I checked the pitch and found that it did indeed have negative pitch, so I adjusted it. I believe I may have disturbed some internal debris, as I now have a different, rhythmic, knocking-type bang at mid-cycle. I can identify that the sound is at the last 4 sections (toward the vent) and sure enough, those sections don't heat up. I corrected the pitch problem - what can I do about this?


  • ChrisJ
    ChrisJ Member Posts: 14,947
    How much pitch did you get on the radiator and what pressure are you typically running?

    Oddly enough, some of my large tube radiators have negative pitch and even a bushing where the valve connects so they always hold some water but it's never had an effect. Perhaps column type are more susceptible?

    Can you post a picture or two of the radiator and how it's piped?

    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • KC_Jones
    KC_Jones Member Posts: 5,430
    Is the boiler still firing AND the radiator isn't heating up? It is fairly common for the thermostat to be satisfied and the radiator isn't all the way hot.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • subaru400
    subaru400 Member Posts: 33
    ChrisJ: I'll check the pitch and post a pic Saturday when I get home. Running .5psi
    KC_Jones: Yes, but the radiator was fully hot before the first 'fix', I think the steam is being hindered within the radiator after I shimmed it up. Is there a good way to clear it?
  • Fred
    Fred Member Posts: 8,541
    Is the vent on that radiator working properly? I doubt that it is block inside the radiator but the vent may be failed closed and the steam is pushing the air as far into the rad as it can and then it stops.
  • subaru400
    subaru400 Member Posts: 33
    Yes, the vent is working. I am not 100% on my guess of blockage, but the hammer is still there - different quality to the sound and more consistent/frequent, but still there . . . almost would have wished I left it negative tilt :( Thanks! I do have some VariValves on order, so we'll see if that makes a difference when they arrive next week.
  • Fred
    Fred Member Posts: 8,541
    Check the pitch of the pipe that feeds that radiator in the basement. It is possible that tilting that radiator back towards the feed pipe changed the pitch of that pipe just enough that it is now level of slightly pitched the wrong way. If that's the case, see if you can raise that end of the radiator slightly and then repitch the radiator.
  • subaru400
    subaru400 Member Posts: 33
    Fred - good call! That's certainly possible and I'll check it out when I get home tomorrow. I think I may need to put a floor jack under that radiator, anyway, as the floor is sagging under it to a degree (which contributed to the negative pitch), so I'll have to make likely adjustments to maintain the drop, anyway. Thanks!