This morning I noticed something strange with the faucet in my tub. It is a single handle tub shower faucet made by Moen. Rather then starting with the handle down in the off position and turning anti-clockwise to turn on, I need to turn it clockwise to turn on and anti-clockwise to turn off with the handle finishing in the up position. Do I need to replace the entire cartridge or is this something as simple as a washer?