A dangerous issue with a gas furnace installation is addressed, which could have put the customer at risk. The previous contractor used incorrect venting materials, causing leaking pipes and water damage near the furnace. This problem created a potential carbon monoxide hazard, making it crucial to fix. Watch as the faulty vent pipes are replaced, a mechanical coupling is installed, and proper sealing techniques are used to ensure safety. Key tools like the PVC shear and impact driver are highlighted, along with the importance of following code requirements to prevent future issues.