On Jan 6, 1:23*pm, "Ray" wrote:
Yes, ours is a single-pipe system delivering steam.

But what do I do about the "knocking" problem?

"Bubba" wrote in message

...



On Sun, 06 Jan 2008 15:48:39 GMT, "Ray"
wrote:

Sorry to be such a pest, but I have another question about our aging steam
radiator system in our six-unit apartment building. Last night, an hour or
so after the weekly flushing of the systerm, we heard a very loud knock in
the pipes. As if someone had hit the pipe with a sledgehammer.

Is this dangerous? What should I do? Was the knock, which we heard only
once, probably tied in with the flushing?

You most likely have a one pipe steam heating system. The "knock" was
steam hitting the cold condensate water coming back the same pipe.
Yes, it can be VERY destructive.
Bubba- Hide quoted text -

- Show quoted text -

You may have radiators not pitched to drain the water if you have
removed them to refinish floors or paint, or the building settled,
just check they angle, a shim or wood can be used to raise one end. In
blowdown I do the low water shutoff and a drain at the bottom of the
boiler for about 5 seconds maybe every week or 2 if it continues and
you are not overfull maybe the building has settled changing the pitch
of a pipe.