rattling sound coming from radiator

Big Ed_4

With thermal expansion caused by expanding pipes . The noise is more rapid when it first heats up and then the noise is less and slower when it cools down .

You mentioned it only makes noise after it cools down for a while . Makes me think of a pipe is able slide on expansion but grabs as it shrinks back to size.

Bob_121

greetings to all the pros on the wall.

i have a question regarding 1 pipe steam heating and its about noise stemming from radiator.

my piping is up to code per manufacturer instructions and i have new varivalve on this radiator. it heats up all the way across however when steam starts to fill the middle of the radiator, i am getting annoying rattling sound every heating cyle. sounds like someone taking a screw driver and hitting it back and forth across 2 columns of the rad or to be in perspective, it sounds like a pinball in in the radiator bouncing around.
what can this be? I have proper pitch on this radiator but now im stumped.

last radiator question. I have another radiator that seems to bang during the cool off stage. The temp is satisfied and after bout 45 mins after the stop calling for heat, the unit bangs every now and them. what can be the cause of this banging?
Many thanks!

Big Ed_4

Banging

The first radiator seems to be holding a puddle of water between the sections.. I would first give it a greater pitch back to the supply pipe ,make sure supply valve is fully open . After that pull the radiator and flush the insides out .

The second radiator may be a thermal contraction . Which I never came across without the expantion noise as well . I would look where the supply pipe comes through the floor. Thermal expantion and contraction noise generaly is metal sliding accross wood . It first grabs and then breaks loose...

Bob_121

many thanks on the 1st explantion.

Thermal explantion? i does not sound like metal sliding across wood floors but does sound loke a popping noise.

how does one get rid of this?

Big Ed_4

Expantion noise

remove some of the wood that rubs along the metal pipe. Or push a rag , not too tight between the both. Or cut a sliver of plastic from a soda or milk bottle and slip it between to make a glide ... Soap works but can wear off .

Look where the pipe goes through the floor or the piping in the basement . Metal againt wood..

Bob_121

biged, but i believe the noise is coming from supply valve.
its like a POP sound...
is this thermal expantion?

thanks agian

Bob_121

Thanks BIG ED.