bang in the night

rcrit

The radiator in my bedroom bangs and ticks a bit during the night (it's been mild during the day lately). I stuck my 2ft level on it and it was just about dead level so I jacked it up about 1/8" or so on the vent side (one-pipe). The bubble is still in the center, just off to the extreme of one side. It made no difference in the sounds, except the ticking may have changed key.



When getting the pitch right is there a rule of thumb for how far out of level to go? I know that going too far means it could move the condensate too fast and/or disturb the muck at the bottom. Is the idea to do as little as possible, so I might try shoving my shim in a little further a bit at a time?



I hear the sound twice, not very far apart, maybe 60 - 120 seconds. I have a Hoffman 75 on the main feeding it and I've generally felt a security in the thunk it makes when it opens and closes telling me "Your main vent is working." I wonder if I'm hearing the reverberation of this in my radiator. Am I nuts?



BTW, I discovered that the previous homeowner had jacked up one of the legs with a quarter.

jpf321

quarters under the legs ....

maybe he was a wallie that lived there !! quarters make great rad shims .. and they only cost $0.25each.



has anything else changed in the system that may have resulted in the new(?) banging?



are you sure it's water banging and not just expansion noises .. normally when someone says "ticking" that's expansion .. especially if the rad cooled significantly since last cycle. also a pipe rubbing again a wall or floor opening could be heard as it expands .. i have a main that rubs slightly .. that's the signal to me that the boiler is on because otherwise, the system is dead quiet.

rcrit

definitely 2 thunks

There are definitely 2 thunks, spaced a minute or so apart (who can tell at 4am).



I get ticking too and I think I'm just going to have to live with that. This particular riser currently goes up through a piece of built-in furniture so there is tons of opportunity for hitting wood. I can live with this, and heck, I can live with the thunk, but if it really is water hammer I don't want my system ripping itself apart.

jpf321

rubbing suggestion

it has been suggested several times here that sliding some cut-up plastic milk container material between the rubbing pipe and wood will allow more frictionless interaction...



see it you can work on this very cheap project by jamming some milk plastic anywhere you suspect a rubbing to occur and report back.



jpf