The UPS15-58 is the standard for most residential heating systems. The 3-Speed pump motor provides 3 distinct pump curves enabling it to replace over 30 different competitors circulator pumps. Comes with built-in check valve and rotated flange orientation. The pump is of the canned rotor type, i.e. pump and motor form an integral unit without shaft seal and with only 2 gaskets for sealing. The bearings are lubricated by the pumped liquid.