HFL stands for "High Flow Limit." This code is automatically generated by the spa hot tub's control system when it detects a problem with water flow. Generally, an HFL error indicates insufficient flow or overheating in the spa hot tub's heating system.

"SnS" and "Sn" are two error codes that specifically indicate the status of the Balboa spa hot tub temperature sensor. They inform users of faults related to the temperature sensor in the spa hot tub.