What must be preserved when defective material or parts are replaced or repaired?

When defective material or parts are replaced or repaired, it is crucial to preserve the original approval listing. This listing represents the manufacturer's certification that the material or part meets specific safety and performance standards. Maintaining the original approval ensures that any replacements or repairs comply with the same standards that were required for the initial installation. It helps to ensure the system's safety, reliability, and efficiency remain intact after any alterations.

In practice, adhering to the original approval listing helps in ensuring that similar materials or components are used, which is essential for maintaining the integrity of the installation as it was designed and approved. This is especially significant in mechanical systems where the interaction between components is critical for performance and safety.

The original design, original installation, and original manufacturing specifications may provide valuable information, but without the approval listing, there’s a risk of using parts that do not meet necessary code requirements. This could compromise the system’s operation and safety. Therefore, focusing on preserving the original approval listing is essential when making repairs or replacements.