In the bathroom in the basement, we have a stand alone shower unit that when you turn on the hot water, it whisles at low volume. It doesn’t do it all the way on. The cold doesn’t do it at all. What could be the problem?How can I ifx it?
It could be the shower head, the mixing valve, or an air-lock in the pipes. Try taking the shower head off and see if the noise is still present.
If the noise continues, turn off the water at the main service entrance and inspect the mixing cartridge inside the mixing valve. On most valves, you first remove the handle by prying off the center cap to expose a screw, then unthread the screw to remove the handle. This should expose screws that allow you to remove the escutcheon plate (the decorative plate that hides the plumbing). The valve body will either have a place for a wrench to unthread the top of it, or a clip assembly that you pry off, to be able to access the diverter inside the valve. The diverter sometimes threads out, and sometimes requires you to gently use a screwdriver to pry it out.
On particular brands, there are other parts inside. Delta faucets, for instance, have springs and a black rubber seats that wear and can cause noise. Inspect the gaskets and o-rings for wear, and repair or replace the diverter and other internal parts if necessary (take the parts to the plumbing department to make sure you get the correct replacement.)
After reinstalling the internal parts, remove the shower head and turn the water back on. Allow the water to flow in the HOT position for 3 minutes, then in the COLD position for three minutes to purge air out of the system.
Note: on shower/tub combinations, the diverter in the tub spout is another common source of a whistling noise.