!!
critical Silvercrest

Error Code S B

Spa is shut down due to a failed or malfunctioned plug socket 'B' sensor.

? What Causes This

Faulty sensor in plug socket ‘B’

How to Fix It

Check the correct operation of that sensor and seek service assistance if unresolved.

Source: page 8 of the official manual

From the manual

Manual page 8 — Silvercrest error S B

This error code appears in:

Silvercrest Sfb 80 A1 Foot Spa