Final answer:
Flushing a system with water is not an EPA-approved method for cleaning a system after burnout because it can lead to further corrosion and damage. Instead, using a vacuum, chemical solvents, or brushes that do not harm interior surfaces is recommended.
Step-by-step explanation:
According to EPA regulations, the procedure that is not an approved technique for system cleanup after burnout is flushing the system with water. This method is not recommended because water can cause further corrosion and subsequent damage within HVAC systems. It's essential to use appropriate techniques such as using a vacuum to remove debris, applying a chemical solvent to dissolve residue or even using a brush for mechanical cleaning, provided it doesn't damage the interior surfaces.
For example, a dry-cleaning solvent and fire extinguishers have been used in the past for cleaning purposes, but they are no longer recommended due to environmental and health concerns.