If I physically press the float switch, the pump will function properly. When the reservoir fills with water, sometimes the pump is triggered while other times it isn't until the point water spills out the basin. When the basin is filled, sometimes the lightest touch will trigger the switch. I'm guessing the pressure from the water isn't high enough to trigger the switch in all cases. I've opened the pump and there doesn't appear to be any buildup or debris. The pump is two years old. Any help is greatly appreciated before I go purchase a new pump. Thank you.