Very loud hammering in my hot water pipe

[michdet]

I get very obvious hammering in my hot water pipe under toilet sink.
However if turn both hot and cold the is disapper instantly.
Please advise how to fix this problem?

[HayZee518]

in the hot water line above the valve install about a foot of tubing with a cap on the end. this will provide an air gap or air cushion. it will absorb the sudden pressure surge and negate the water hammer.

[Redwood]

I'm reading this as you saying you get a loud hammering noise while running hot water only at the lav sink with the noise disappearing when you either shut off the faucet or, if you also turn on the cold water.

You have a loose washer on the hot angle stop valve. The valve should be replaced.

What temperature is your hot water set at?
Extremely hot water can soften the rubber washers.

[st_browndc]

I also think you have a loose washer somewhere in there.

[dreamland]

Hi

I replaced my Valve but problem is still continue. My plumbing service provider told me to change whole pipe.

Is this right?

[HayZee518]

you need to install a water hammer nipple somewhere above the valve.

[dreamland]

hi

Thanks a lot.

[HayZee518]

I'm sorry but that is the normal fix to water hammering. you could try to make a loop in the tubing feeding the valve or put an expansion tank in the line.

[Redwood]

Water Hammer is caused by the momentum of the water slamming to a stop and rebounding several times. In which case a hammer arrestor installation is warranted.

A hammering sound while the water is flowing is not water hammer and in almost all cases is caused by a loose washer or, debris in the water stream.

The cost of an expansion tank for installation in a water hammer application is cost prohibitive.