When I turn the hot water on in the kitchen sink there is a hammering sound in the hot water pipes. It doesn't happen when I turn on the cold water. I got under the house and I can feel the vibration in the pipes. The house is about 30 years old and it just started making the noise. No plumbing work has been done on the house in the last 2 years when a cold water pipe (copper pipe) had a pin hole in the pipe.

Jeff

Gas or electric water heater?

Gas.

Jeff

Gas.

Jeff
Thanks Jef,
Is the vibration stronger near the heater or the sink?

At the sink.

Jeff

OK Jef,
That eliminates the heat nipples and the water heater. The problem lies in the sinks valve. Turn the water off to the sink and open up the valve. Check the inlet ports on the cartridge for any trash or crud. Now place a pan over the open valve body and turn the hot water on for a moment to flush out the valve body and the hot water supply. Reassemble and test. Better now? Regards, Tom

I did what you suggested and then turned the hot water back on and no hammering. However, sometimes it has to run a long time before it start making the noise so hopefully this was the solution to the problem. Greatly appreciate you help.

Jeff

You can also secure the pipes.

The first thing I did the pipes started making the noise was get under the house and secure the pipes. I ran the hot water for a good hour and NO noise. Thanks again.

Jeff