Tapping sound in pipes-Steam heating.

Bernard

Help! I have had steam system that has worked well for many years. This year there is a tapping sound(not large banging when you have too much water -I know about that). It wakes us up . Any ideas what to do besides tearing out the pipes. Will appreciate any advice!

Rod

"Tapping Sound"

Hi- Just a few questions to give eliminate some possibilities. Anything been done to you steam system since last heating season?  Has there been any construction that could have disturbed the steam system piping? Does the boiler water line in your sight glass bounce up and down much?

- Rod

FJL

Pipe Expansion

Do you get this sound at the start of the heating cycle? When the steam turns on? If so, the tapping could very well be a sound created when the steam hits the pipes and causes the pipe to expand and rub something. I had a section of horizontal pipe replaced because it was back pitched and causing loud water hammers. After the fix, I get a tapping sound every time the steam turns on and the steam hits that section of the system.



If anyone has any idea how I can fix it aside from opening up the floor, please let me know. The tapping wakes me up also.

Bernard

Thanks for your reply

No that is the intesting part -nothing has been done over the past five years.

The glass seems to be bouncing about one inch. appreciate any advice.

Jamie Hall

Think of it

as ghosts.  Friendly ghosts.



More seriously, it is almost certainly an expansion noise, and these can appear after years -- decades -- of silent operation.  What I think happens (I have a few in the building I superintend) is that with time, the radiator inches its way across the floor (well, micro-inches?) -- moving just a little bit with each cycle.  Particularly big radiators.  Eventually this may bring a pipe somewhere into contact with wood -- typically in my building, a riser into contact with the floor.  Then you hear it tapping as it expands (or contracts).  I've had several radiators do this, and the solution was to inch them back to where they started, 80 years ago...



In an older building, another possibility is some of the building shifting slightly and contacting a pipe.



Only solution is to try and locate exactly where the problem is, and then figure out what is touching what, and why.