517. Support: Balboa topside displaying (SnA or Sa)

The Sensor Connected to the "Sens.A" Connector on the System Board may have failed and Spa Functions are Disabled. Check and Test Sensor A, Cable, and Connector for Damage, Connection, and Operation. Check the following: 1. Make sure Both Temperature Sensors are Properly Mounted at the Heater. 2. Check Sensor Wires for Cracks or Damage. 3. Make sure the System Board Sensor Connectors are Clean and Connected Properly. 4. Check to see if either Sensor appears to need to be Replaced, and Replace as Necessary. 5. At the board unplug both sensors SEN A and SEN B then switch connections by plugging SEN A to SEN B to see if the SNA messages continue.