HVAC furnace systems rely on gas valves to regulate fuel distribution and maintain controlled burner performance during operation. When these components develop faults, furnaces may encounter ignition problems, weak heating output, or unexpected shutdown cycles. This guide highlights seven common furnace gas valve issues and explains the corrective measures typically used to resolve them. It covers valve calibration concerns, electrical connection failures, and contamination that may affect fuel delivery inside the system. Designed as an informative overview, the material outlines troubleshooting methods and repair considerations associated with maintaining stable and efficient furnace operation in HVAC applications.