Our stall shower with a single-handle control doesn't deliver hot enough water. Seems like it's mixing in cold water even on the hottest setting. Is there an adjustment? This is the control:
There might be an adjustable "stop" that limits how far you can turn toward hot. Take off the handle and see (there's probably a set screw on the underside of the handle.)
That faucet is a Moen Monticello with the common moen positemp rough in valve. Here is a web address to a pdf of the instructions for this faucet. http://www.moen.com/shared/pdf/instruction_sheets/ins2033.pdf There is an adjustable temperature limit stop underneath the handle (if the installer put it in) made out of white plastic. You need a small hex key wrench to loosen the set screw on the underside of the handle, and there is another piece under the handle held on with a phillips head screw. Take that off and you will see the limit stop, if it is there. It is actually 2 pieces that mesh together like gears, and depending on the way you position the 2 pieces together is how far it will let the handle turn (turning the handle counter-clockwise, the hotter the water gets). to set it so the handle can go all the way as hot as it will get, put the pieces together so that the 'tabs' are lined up together, and insert the pieces back into the metal piece that they were in with the tabs straight up. When you put the piece on there that the handle screws onto, rotate it to turning the water on and you will see how that works.
If there is no limit stop pieces in there, or after adjusting it, it still does the same thing, then it is a problem with the cartridge. Either there is something stuck in there or a defect in it. The cartridge is under the limit stop. You will need to shut off the water in order to pull that out. Here are some instructions from moen on how to service the cartridge. http://www.moen.com/shared/pdf/instruction_sheets/ins746f.pdf You will have to dial the 1-800 number for moen to order a cartridge rebuild kit (they will send it to you free of charge).
Or call a plumbing professional like myself to fix it for you. Good luck--The Captain