You're probably right that it's not a drip, but that's the best way I
can describe the sound. There is no sign of water damage in the room
below.

As for how much tearing I woudl be willing to do.... it sounds like
it's just below the floorboards under the radiator... I can even feel
the "drips" happen some of the time. what would I have to do to
prevent the soudn if I were to pull up the floorboard? Wrap the pipe
in cloth or something like that?

As for the cold radiator, it actually worked about a year ago, then
suddenly stopped. When I bleed it, it still has pressure, so I don't
think the pipes are clogged, and nothing else has really changed in the
system... what could cause it to suddenly stop getting flow like that?

In the mean time, I might do as you say and just set the thermostat an
hour or two later... If I were to turn off the valve to that radiator
and just use a space heater in that room, do you think that would stop
the expansion, or would the general heating of the system still cause
the problem?

Thanks so much for your help....

Dan


On Jan 3, 9:44 am, Speedy Jim wrote:
wrote:
So, I live in an 80 year old house, with a gravity based hot water
radiant heat.

In my bedroom, there is a radiator, and every night, around 4-5am, when
it starts warming up a drip... drip... drip... sound starts. And I
cannot sleep through it. Earplugs used to work, but not anymore. It's
like a drill going into my head.

So what can I do? What's Causing it?

If i kick the radiator (which I know is probably not hte greatest
idea), it stops for about 30 seconds, then starts up again. Just long
enough for me to get my hopes up. When it started this morning, the
radiator wasn't even warm yet, so I don't think it's floorboards
expanding... I could be wrong though.

Here's the setup of the system, and what I've tried so far:
3 floors, 15 radiators (13 working, 1 cold, 1 shut off), 5 per floor.
Gas furnace, expansion tank next to the furnace in the basement (is
that weird?)

The system had been filled to 20 PSI, so I just upped it to 25 PSI,
bled all the radiators, and refilled back to 25 PSI again. No luck,
still getting that damned sound.

I've tried spraying the intakes to the radiator with WD-40, I've tried
pushing pillows under the radiator to dampen the noise (it didn't...
just changed the tonal qualities a little), I've tried cursing at it
and praying. Nothing has worked.

Please.... Please... PLEASE Help!!!

Also, if anyone has any clue why one radiator would be cold, yet still
spits cold water when bled, I would welcome some help with that too... I bet "drip" doesn't accurately describe the sound. That suggests
water leaking. More likely that it *is* movement of the piping
(expansion) rubbing on some framing as it goes. 3 floors high
could have a *lot* of expansion. How much are you willing to tear
out to find it? And if the system is 80 yrs old, I would be
fearful of doing *anything* which might cause a pipe failure!

In a gravity system, everything must be "perfect" for flow
to occur. Even one small length of pipe set with the wrong
slope can impede flow to a radiator.

Expansion tank can be most anywhere on the system.

Would you be willing to simply set the 'stat to turn on
later in the morning?

Jim