I fixed a Water Knock that started about 2 years after we moved into
OUR new home (the house itself was not new.)
Now we get a knock when turning off the HOT water.
Do I fix it the same way - cut off the water, open the lowest drain (
the water hose faucet) then open several fixtures in the house
draining the water in the knock arrester.
I believe that is right - it fixed the knock in the cold water any
way.

But, is it the same for the hot water knock? Or do I need to do
something with the water heater to open it to atmospheric pressure?

Any help would be appreciated so I don't screw up the new water heater
I managed to install without any cussing or screw ups.

Thanks
RC