To start, you will need to remove the entire handle by unscrewing the accent piece and loosening the set screw. Once the handle has been removed, you will see a small gray disk, remove this cap and set it aside. You will now see a white or gray plastic piece with a triangle shape on it. This piece is called your rotational limit stop and is what will be adjusted.
First, ensure that the silver pin running through the brass stem is as far away from the triangle as possible. Lift up on the round piece with the triangle on it and rotate this piece counterclockwise. Each notch you reset it will increase your maximum hot water by three to four degrees. On the outside of the cartridge you will see small notches, these notches indicate how far the cartridge can be adjusted.
Once you are finished, place the gray disk back on the stem of the cartridge and reattach your handle.
I hope this information is helpful.