Display shows lowercase 'b'; door stops in partially open position.

Safety first: Keep clear of the door while testing. Disconnect power before opening covers.

Step-by-step:

• Check control inputs: Ensure no external switch is wired to the partial opening input that may be stuck closed.
• Reset partial opening: Enter the programming mode and delete or re-set the partial opening position according to the Hormann manual (often by moving the door to the desired position and storing it).
• Relearn full travel: Perform a full open/close learning cycle so the operator correctly knows the end positions.
• Test: Use the main open/close button. If the door still stops at the same partial point and 'b' shows, the memory or encoder may be faulty.