Noise in pipes. is it air?

Question

when i turn off my cold water faucet, i here a noise from the pipes that sounds like a ship fog horn . the sound only lasts for a few moments. it started after i changed a part in the toilet. please help

Answer 1

You have air in the lines and or loose pipes that rattle when the water is flowing through them.(it's called hammering) You may have to install (or have one installed) what is called an anti hammering devise. It is connected/soldered to your incoming (I believe) water line near your water heater. These copper pieces are easily purchased at your local hardware store. They have instalation instructions on the package. Good luck.

Answer 2

You have water hammer... you can try opening up the angle stop on the toilet (valve that supplies water to toilet.)  Basically, when the float stops filling the tank, the valve "hammers" a bit and creates the noise you hear.  usually a quick fix for this is bending the float rod downward a little.  good luck.  That or get the non-float style toilet guts.

Answer 3

It may be water pressure trying to close the water input valve in the toilet tank. No sure what part you changed in the toilet but my guess is that the wrong part was changed or installed incorrectly.

Toilets can be tricky to fix.

Answer 4

Allan, yes the term is "water hammer", but it means that there is NO air in your lines!  All water systems need some air in the lines.  When there are no faucets open, water is sitting idle, waiting for an open faucet to flow from.  When you open a faucet, water starts to flow through this faucet.  For clarity sake, lets say the water is flowing at 2 gallons a minute.  Now you shut the faucet off.  The water is still moving through the pipes, only now there isn't an open faucet for it to flow through.  The forward motion of the water has stopped, and a reverse motion has started.  If there is no air in the lines, any pipe that is loose or not secured properly, will start to rattle.  There should be a pipe that projects vertically off one of your pipes, and it will be capped off, or not connected to anything.  This is an air chamber.  Over a period of time, the air that should be trapped in the chamber, will be forced out, and with no air inside, it can't do it's job.  All you need to do, is turn off the main water valve.  Now open all the faucets, and let them empty.  Once there is no more water coming out, close all the faucets, and turn the main valve back on.  This will replenish the air in the chamber, and eliminate your "water hammer".  Cost: nothing but about 5 minutes of your time  Result: peace of mind

Answer 5

yes it is air