Quality Plumbing Supply stocks hundreds of shower valve thermostatic cartridges from all the major shower manufacturers. We also carry reverse thermostatic cartridges for when your shower water lines were crossed on installation. Replace your shower valves thermostatic cartridge with a new thermostatic cartridge and get your shower water mixing correctly again.
If your shower valve is not mixing the water correctly, the handle is very hard to turn, too easy to turn or if water is leaking from around the handle you may need to replace your showers thermostatic cartridge. You should also check the shower valves check valves to make sure they are operating correctly.