I started having trouble when the water line was proken during digging around the basement. The line was repaired however some gravel was sucked into the pump and had to be repaired. The pump now suckes air and has trouble pumping to it's max. setting. I disconnected the line after the check valve at the pump and connected a line from there straight to a large container of water and started the pump, it still sucked air. Can the pump have a leaking gasket or something that can suck air but not leak water or lose pressure?