Shower Squealing

[Mbiallas]

I have noticed lately that while taking a shower that a high pitched whining or squealing comes and goes. It seems to be coming from the mixing valve but isn't constant. A 5 minute shower will have 3 or 4 cycles of no noise v noise each lasting 45 seconds or so. Does this sound like it could be caused by air in the line or do I just need a new shower setup? Thanks in advance.

[wa8yxm]

I have noticed that in many showers/etc at low flow rates... IT's the mixing valve usually. It is "Whistling" same as when you whistle.

[MFL]

Showers typically have a flow reduction to save water. It may have started to plug up a little causing even more reduction, thus the squealing sound. If on city hookup, the pressure may be surging at times, causing a noise in the system.

Depending on the cause, it may help to drill out the reducer a little, or remove it, if saving water is not an issue.

Jerry