Foot valves help keep a pump primed therefor stopping your pump from burning out. They are a type of check valve but are used at the end of a pump suction line. Remember to buy a good quality foot valve as they may not be easily accessible after installed.
A foot valve is a type of check valve that is typically installed at a pump or at the bottom of a pipe line (hence the name). Foot valves act like ball check valves, but have an open end with a shield or screen over it to block debris from entering the line