Water heater whistling when we use hot water
This is in a new construction home that's about a 18 months old.
It's been happening since we moved in. I had my builder and plumber look at it and they said everything was fine and it was normal. Both water heaters are gas and do the same thing. They are in the basement, but we can hear it upstairs on the first floor and it drives me nuts. It only happens while we are using the hot water. Any ideas?