You park a trailer with compressed air-braking system for a short period. How can you disengage the service brake of the trailer?

To disengage the service brake of a trailer with a compressed air-braking system, it is crucial to understand the functionality of each method.

1. Activating the release valve is essential as it allows the air to escape from the brake chambers, thereby disengaging the service brake effectively.

2. Venting the brake line can also be necessary in certain situations as it helps reduce pressure in the brake system, ensuring that the brakes are not applied.

3. Releasing the parking brake is important because the parking brake can engage while you are dealing with the service brake. If the parking brake is still applied, the service brake may not disengage fully.

According to German traffic regulations, it is vital to ensure that all brakes are correctly managed to ensure safety during operation, especially when dealing with trailers. Therefore, each of these actions is part of the correct procedure to ensure the braking system is fully disengaged when needed.