Hello,

We have a shower with a single lever faucet (American Standard) that has recently started shrieking -- although this only occurs when we turn it on on the hot water side. A very high pitched whistle will start up after a couple of minutes, presumably as the water gets hot. The whistle stops if we turn the handle towards the cooler side, and we can also turn the handle back to warm/hot at that point without restarting the shrieking.
So really it only happens upon starting the shower on the hot water side, if that makes sense.

Thanks!

You have debris in thye valve or a washerlike flap diaphram is coming loose and vibrating. Repair ir now before it gets worse. Shgut off the main, remove the handle and the escutcheon plate then pull the cartridge. Let us know if you need more help.