A few days ago, one of the showers in our house started running water at very extreme temperatures. It starts really cold but then escalates to scalding temperatures. Normally, the water is cool when you first turn it on and then you can turn it more to the left to increase its temperature. But now, no matter where you have the knob set at, the water is really really really hot. This only happens in one shower; the water for the rest of the house is fine.

Is that Single Handle shower valve ?

Yes

Just bumping this question up to see if anyone has an answer. Thank you.

I think your cold inlet is partially clogged on the mixing valve cartridge, kind of rare but not impossible. Do you know how to remove the cartridge to clear it? Brand and model could help me give more details

Sorry, I don't know how to remove the cartridge/am not even all the way sure where exactly it is. I know the brand is price pfister but I don't know the name of the model. I googled pictures and it kind of looks like a J174-BC 100 Series Shower Only but ours is a tub too.

I agree with Bob. Sounds like a cartridge problem. The cartridge is what the handle is connected to. Hope one of the guys can give you some info as to how to remove cartridge, as I don't work with price pfister much, so can't remember exact disassembly procedures.

Just bumping it up again to see if anyone can help me with removing the cartridge. Thanks!

Krissa, MGD and I are both at a stopping point. He doesn't have the daigrams and I am at a remote location with a terribly bad computer and can't get my files. I don't know if this will help Price Pfister Cartridge Assembly Removal

I agree with Bob and MGD it could be the cartridge open the link which Bob have posted will tell you how to remove and replace the cartridge and also open the link below will show the valve with all the parts, Thanks.

John

http://www.plumbingpartsdepot.com/ppavante09sltub.pdf

I will try to see if I can take it apart. Thanks for helping me find out what the problem is!