It’s an ancient dual hot/cold thing in the bathroom. Looks somewhat like this one, except for the fact that mine is nowhere near as hi-tech as the linked unit. There’s the hot knob, the cold knob and the outlet in the middle - all steel - and that’s about it.
Recently, the cold part stopped working: turning the cold knob to the max releases only a bare trickle of water. Hot works just fine, though, and consequently, showers have become very uncomfortable events. Hot without any cold to mix it with = ouch.
What could be wrong with it? Is it something I can fix with a wrench and a new washer, or should I call in a plumber?
(Please note that my plumbing knowledge is zilch currently. I’m hoping your explanations will make me less of a dunce and more confident about handling such minor (?) emergencies myself.)
If the cold washer has worn to the point that the screw securing it has become wedged in the seat, the scenario you describe is plausible. Shut off the water supply, disassemble both sides and replace the washers. The catch to this is that since you’ve said it is a shower, you will need to remove the handle escutcheons, and you’ll probably need a set of deep sockets used for disassembling shower valves.
When strung together, they make a sound similar to wind chimes. Think of them as prayer bells for the plumbing gods.
The handle probably isn’t turning the inner mechanism because the moving parts are wearing down. The handle is generally attached to a stem nut of some sort, and the nut turns the stem that controls the water flow. If the edges of the stem nut or the stem itself are worn, the handle won’t turn the stem.
Turn off the water supply to the cold water faucet in you tub., and then run the cold water for a second to clear the pressure in the line. Unscrew the screw that holds the “Cold” handle to the front of the faucet. Under the handle, there should be a nut. Unscrew the nut. Under that, there should be some sort of cartridge or spindle that controls the flow of the water. (Here is a decent diagram that shos some similar faucet innards. Here is another.) It may be as easy as cleaning some gunk out of the gunk out of the workings, but more likely you’ll just need to replace the stem, or the cartridge, or whatever’s in your particular faucet. Take the relevant parts to the hardware store with you and see if one of the employees can help you find a suitable replacement.
Good luck.
Its probably plugged up with sediment in a little screen before the water gets into the cartridge which is a simple fix. BUT if you know nothing about plumbing those newer types are a bit more complex than a standard washer and seat. I’d call a plumber
