We have 3-year-old shower with a "pressure-balanced" valve that is suppose to keep us from getting scalded when someone flushes the toilet. It worked fine for a while, but now temperature control is erratic and the valve makes a "thunk" noise when you turn the control handle quickly.
I hoping that I can:
Replace a cartridge or something, so I don't have to..
Tear out the the builtin closet behind the valve to replace the whole thing.
You can see some pictures of the valve below. It's Moen and I think it is "posi-temp" (their pressure-balanced trademark), but I can't find this particular valve online anywhere. In particular the large flat head "screw" on the right is missing from the valves I see on Moen's website and for sale at various places (Is it maybe an extra output port, I'm not using?).
Further complicating things, the "manual" Moen provides for other PosiTemp valves is nearly useless for purposes.
So, in summary, my questions are:
- How do I figure out what valve this is?
- How do I find useful documentation about this valve?
- What do I need to do to fix the "thunking" sound and regain control over our water temperature?