Is error 0x20B1 a fault or a warning?

0x20B1 is a warning: the unit keeps running. Fix the underlying condition before it escalates.

How do I clear or fix error 0x20B1?

Send faults externally, cluster disables insulation detection function. Recovers on normal sampling.

0x20B1

Battery cluster SBCU internal bus voltage sampling fault (after applying high voltage)

Warning — a protection warning — the ESS unit keeps running, but deal with the cause before it escalates.

Energy storage systemWarning

Battery cluster SBCU internal bus voltage sampling fault (after applying high voltage)

Cause: Invalid internal bus voltage sampling.

Source: FLS-ES232LC-S.pdf

What does error 0x20B1 mean on a Felicity ESS?: 0x20B1 means: Battery cluster SBCU internal bus voltage sampling fault (after applying high voltage). Invalid internal bus voltage sampling.
Is error 0x20B1 a fault or a warning?: 0x20B1 is a warning: the unit keeps running. Fix the underlying condition before it escalates.
How do I clear or fix error 0x20B1?: Send faults externally, cluster disables insulation detection function. Recovers on normal sampling.

Compiled from official Felicity user manuals. Always consult your device manual and a qualified technician before performing repairs.