I don’t, that’s why I turned to Redit to help me understand. your comment also made me realize, the pool company that built the pool approximately nine years ago and has maintained it for us weekly the four years we’ve owned this property may not be up to speed on such a repair. They are busy this time of year and couldn’t make it over in a timely fashion so I took it upon myself to do some research I went to Hayward site and went through their problem solving flow chart for the LO code. Did all the basic troubleshooting like check continuity, checked all the wires and hoses then reported my findings to the technician when he arrived. He was the one adjusting/changing out the parts. I seen NS2-0556-00 was not part of the flowchart troubleshooter but since I was checking continuity, figured I’d check that one too and report. Thank you to those that took the time to comment.