This Balboa Circuit Board, PHTLXR1A Digital, 52382 is OBSOLETE. This circuit board uses a pressure switch to monitor water flow.
See generic replacement 52295-01, or consider a new replacement controller that comes with a new heater, topside panel and cords.
When selecting your spa circuit board, it’s critical that you go by part numbers and not appearances. The part number on a spa circuit board can be found on a white sticker located directly on the circuit board. Buy based on this part number. Do NOT purchase a hot tub circuit board just because it looks the same as the one you’re replacing. Spa circuit boards can look identical, but be programmed differently to work with different spa controllers and topside panels.