When I pull the shower diverter in our bathroom it makes a very loud squealing sound. It only makes this sound on hot water settings... turning back to cold water stops the sound. It takes a about 5 seconds for the water to come out of the shower head and the squealing continues while hot water comes out. We have a single knob for water temperature and the diverter is in the tub spigot. I soaked the shower head in CLR and it has not helped the issue. I tried the diverter with the shower head completely removed from the pipe and still get the noise. Any help would be appreciated.
Thanks,
Dave

Its not the shower head it's the spigot. Put your hand under the spigot to form an air tight seal and see if it continues. From the research that I have done on this in the past it is caused by air getting sucked up into the spigot because the diverter is not making a good seal.

When I pull the shower diverter in our bathroom it makes a very loud squealing sound. It only makes this sound on hot water settings...turning back to cold water stops the sound. It takes a about 5 seconds for the water to come out of the shower head and the squealing continues while hot water comes out. We have a single knob for water temperature and the diverter is in the tub spigot. I soaked the shower head in CLR and it has not helped the issue. I tried the diverter with the shower head completely removed from the pipe and still get the noise. Any help would be appreciated.
Thanks,
Dave
Brad it sounds as though you need to change you shower valve cartridge.

I agree with BillyRay, you need to change your valve's cartridge. There is a problem with either the o-rings or the valving on the hot side of the cartridge that is causing the issue.

Yes yes --- this worked --- the very loud squealing sound stopped, and now how to fix it. Can't take showers with hand under the spigot --- Thank you so much -- TJ in CA.