Hi I have an old Goldline (Hayward) Aqua Rite v1.4 and was told our salt cell had stopped working. So now I am replacing it with a Hayward T-15 for a 12,000 gallon pool; however, upon installation the t-xx is not showing up on on the display when I press the diagnostic button. I was wondering if that is normal for the outdated version of the software or if it was a motherboard issue. We've already had the motherboard fixed once about a year and a half ago. I just cannot remember if the t-xx number was ever there or not. On a side note the No Flow indicator light is constantly illuminated even though there is flow through the system and the cell is perfectly clean. Please any information is great. I am extremely clueless when it comes to these systems. Thanks