Systems and methods described herein provide a vacuum priming system for close-coupled pumps. The vacuum priming system is mounted separately from a centrifugal pump and powered by an electric motor. An auxiliary vacuum pump pulls prime (e.g., water or another liquid) through a solenoid valve that is in turn connected to a connecting tube. At one end of the connecting tube is a screen and prime sensor. The screen filters particulates to protect the vacuum pump, and the prime sensor may detect when the centrifugal pump is primed. The vacuum priming system includes a self-contained control panel with an auto operation mode to only pull power during priming, reducing power consumption over the lifetime of the pump system and improving efficiency.

A float box for priming a fluid pump is provided. The float box comprises a floater inside a float chamber, and an air valve assembly that is operated by the floater. The air valve assembly comprises a valve holder that bounds a valve chamber and an insert opening towards the valve chamber, and a valve body that is inserted in the valve chamber. The valve body comprises a valve cover that closes the insert opening, and a seal holder inside the valve chamber. The seal holder has a seal chamber with an access opening where the seal chamber debouches spaced apart from the valve cover. The air valve assembly comprises a seal element with a seal channel inside the seal chamber, and a valve head that is connected with the floater to close off and release the seal channel.

A float box for priming a fluid pump is provided. The float box comprises a floater inside a float chamber, and an air valve assembly that is operated by the floater. The air valve assembly comprises a valve holder that bounds a valve chamber and an insert opening towards the valve chamber, and a valve body that is inserted in the valve chamber. The valve body comprises a valve cover that closes the insert opening, and a seal holder inside the valve chamber. The seal holder has a seal chamber with an access opening where the seal chamber debouches spaced apart from the valve cover. The air valve assembly comprises a seal element with a seal channel inside the seal chamber, and a valve head that is connected with the floater to close off and release the seal channel.