How do you remove dog urine odor from heating vent?

The best cleaners for cat urine are those found at a pet store. What you need is to use one that reacts chemically to the enzymes and removes the order. Using a product that is a specialized stain and odor removing bacteria/enzyme cleaner, such as "Outright Pet Stain Eliminator," "Pet 'Oops' Remover," or "Stain Gobbler".