Customer advised that there was water on concrete floor of garage near end of return box. Examined under vertical drain pan for cracks and moisture none found in return box or in pain. Homeowner did previously flushed drain line in pan. We flushed system let run and is draining at this time. Did find that float switch was sticky and had some moisture in Reservoir. Replaced float switch with new. Advise homeowner to call us the situation occurs again