How are self-test faults displayed on the indicator?

Self-test faults are displayed as an "F" to provide a clear and immediate indication of a fault condition during the self-testing process. This designation is straightforward, making it easy for operators or users to recognize that there is an issue requiring attention. Using a single letter simplifies communication and allows for quick identification and response.

In contrast, other forms of displaying faults, such as numeric codes, flashing lights, or graphical formats, may not convey the information as intuitively or rapidly. A mere letter, like "F," eliminates ambiguity and ensures that the operator knows explicitly that a fault exists, facilitating prompt troubleshooting and maintenance actions.