G2 Gas Fitter Exam 2025 – 400 Free Practice Questions to Pass the Exam

Spillage of flue gases at the appliance draft diverter indicates a restriction in the venting systems. When the venting system is functioning properly, flue gases are effectively carried away from the appliance, ensuring safe operation. However, if there is a restriction—such as a blockage, improper installation, or design flaws—it can prevent the flue gases from exiting as they should. This causes the gases to back up, leading to spillage at the draft diverter.

Understanding that spillage is a sign of potential issues in the venting is critical for safety. A properly functioning venting system would not allow such spillage to occur, and an excess draft condition would instead expel gases effectively, not cause them to spill. Furthermore, high-efficiency appliances typically have specific venting requirements and are designed to minimize such issues when properly installed and maintained. Therefore, recognizing spillage as a direct indicator of venting restrictions helps gas fitters to diagnose and address safety hazards effectively.