I have a single-handle shower valve problem that has turned into a real headache. We live in a 6 year old house, on city water supply. The fixture in question is Sterling brand and is in a stand-along shower on the second floor. The water pressure is good in the sink faucet and tub adjacent to the shower.

Initial problems: The valve handle turns 180 degrees from right (off/cold) to left (hot). When coming from the off position, the handle had to be turned all the way to the left to get hot water, then the handle could be turned back clockwise past 90 degrees and still be hot, then would get cold all of a sudden. However, if coming from the cold side, it wasn't hot until almost bottomed out at 180 degrees hot. This has been occuring for several months. Then, maybe a month ago, a loud screaming noise started coming from the shower when running (I read that this usually indicates some kind of restriction). Also, the water pressure hasn't been real great lately either. We have a gooseneck extension and rain shower head and it was hardly coming through some of the nozzles in the shower head.

Initial Problem Solving: So, I tried taking the shower head off and cleaning it out. The screen was free of debris, but I also cleaned it with CLR. This past weekend, I took the valve apart. Besides the handle, escutcheon and valve body, it looks to me like the valve really only has two main assemblies. What I think they are called is a Pressure Balance and a Mixing Cartridge (that has the valve stem on it). Please see the links in the previous sentence to see what I think they look like.

They didn't sell parts for this valve at Lowes, so I went to a local place. The guy told me the pressure balance needed to be replaced. So, I bought one, put it in, put the valve back together, and now I have less water pressure than before. The water very slowly runs out of the head now. Now, I will say that when I had the thing apart, my daughter got ahold of the mixing cartridge and it came apart, but I believe I've got it back together properly. Also, when first assembled, the hot was on the right and cold on the left, so I just rotated the valve stem 180 degrees (while still attached) and now the temperatures seem correct.

Can anyone help me with this? I'm very frustrated. I even had nightmares about it over the weekend! Aaahhh!

Thanks to all for your help.