The model number is the easiest way to identify your pump motor replacement. Manufacturers like A.O. Smith do not have a set format for their model numbers. This is dependent upon the specific pump the motor is to be matched with. For example, an A.O. Smith motor that is compatible with Pentair brand pumps may have a model number of B853 or BN24, but an A.O. motor meant for a Hayward pump will have a model number of UST1102 or ST1152. On the motor label there may be a second model number listed, this number generally will begin with either a "C48", "C56", "K48" or "K56" followed by four to nine letters and numbers. An example of this style is C48L2N103B1. Not all manufacturers call their model number by that name, Century Electric refer to theirs as a “Part Number” which has its own unique format. A Century part number consists only of digits and is in the form of“x-xxxxxx-xx”. Extract the middle six digits from that part number and enter it into our search engine for an exact result. A motor model number of any of these varieties can be entered into INYO's product search engine and an exact match can be found.