steam pipe \"clang\" noise

Unknown

the radiator vent that's making the clang ? How old is that vent and the rest of them ? We recommend changing them every 5 years .

But if it sounds as loud as a hammer hitting the pipes I think it's something else . Was the system skimmed and cleaned after the install ? And can you post some pics of the boiler ? An improperly piped or sized steamer can be the cause of loud banging too .

Charlie_17

Steam pipes \"clang\" when radiator vents close!

Recently had my original oil-fired steam boiler replaced (originally coal fired converted to oil). I am now experiencing a clanging noise when one radiator vent closes, which never happened before with the old boiler. If I were to describe the sound, I would say it sounds like someone is hitting the steam pipe with a steel hammer. It has that "ping" sound that a hammer would make. Any ideas what this might be, and how I can fix it?

Brad White_9

Water Hammer

Water hammer is caused by a number of things, most commonly waves of steam building up over pooled water in a pipe then coming to roost at an elbow. It can also be caused by the sudden collapse of steam from vapor to liquid (a 1700:1 collapse ratio, the Black Hole of heating!)

Might the banging be just coincident to the vent closing? Is your observation absolute without exception? (This is not a test of your convictions, rather I am narrowing down the concurrent variables).

Just conjecture and thinking like steam (which has no brain so what am I doing? , this is a hypothesis:

If the banging occurs when the vent closes, the vent ceases to act as a vacuum breaker (by pulling air in). Therefore a charge of steam in the radiator is collapsing at that moment causing an internal vacuum collapse and resultant bang.

I am going out on a limb (and will gladly defer to Steamhead, MadDog!!!, Pat Linhardt and others for their opinion), but I am thinking the vent is closing too soon, possibly due to incorrect location (too high on the radiator perhaps?) or is responding too soon. The way to test this would be to install a true vacuum breaker in addition to the vent and see if this prevents the effect.

One thing which compounds the mystery (to me anyway) is that coal fired steam systems worked on a vacuum-holding principle.

First thing I would do though is to make sure that offending radiator is pitched back so that as little condensate remains in the radiator as possible. Eliminate that variable. The other things to do to eliminate other variables is make sure your pressure is as low as possible (less than 2 pounds or even a pound if you are good) and that the mains are insulated. Just the common things you should be doing anyway. But ocurring at one radiator gives a certain focus.

Brad