Remember, every carpet cleaning method has its purpose. Floor machines can be used to effectively clean the top of the carpet. However, most professionals recognize this method as a "Maintenace" method of cleaning of carpet. This type of method is great for an upkeep on carpeting. Example: the facilities manager of a building wants to keep the carpet clean all year round. The facilities manager may have a carpet cleaner "bonnet" clean the carpet once every week or two to keep the carpet looking good. However, this same facilities manager will probably have a carpet cleaner Hot Water Extract with a portable or truck mount the carpeting once every three to six months fully clean the carpet.
Using a floor machine to clean carpet can only clean the top of the carpet. It cannot remove dirt, bacteria, and stains that are underneath the top of the carpet fibers. Hot water extraction is used to fully flush and extract the carpet.
If you are going to be providing a maintenance method of carpet cleaning, here is a good source for finding the floor machine, pads, & bonnets you need: Floor Machines.