Pipes bang with hot water

[Hcbroughton]

Hey there, first time posting something like this. Thanks in advance for any advice!

This new to us house (built in 1976) has a problem with the hot water. It always happens with the dishwasher and kitchen sink, often happens in the main bath, but rarely happens in the second floor shower. When the hot water turns on, the pipes bang loudly and the water pressure fluctuates. The banging sound corresponds to the pressure fluctuation.

What would be the cause? Here is a video, I hope it’s clear. The sound wasn’t picking up the banging because the water was loud, so I walked around the corner. But yes, the bang is loud! I am sitting in bed listening to it now as the dishwasher runs.

 

[jeffmattero76]

I am not sure of the cause, but this happens in my house occasionally. The solution in my case is to turn the water off, and turn it back on slowly. That seems to stop the banging.

 

[frodo]

because of the water slowing then speeding up.

I would say that the bib washer on the hot water stop under the kitchen sink is loose
if it is not, I would check if a globe valve was used at the WH, the bib washer is loose

to fix. turn off water
remove the bonnet nut and remove stem, remove/replace washer