Which valve automatically shuts off the supply of the gas when energized by a combustion safety control?

The combination gas valve is designed to automatically shut off the supply of gas when it receives a signal from a combustion safety control. This feature is critical for ensuring safety in gas-fired appliances, as it prevents gas leaks that could lead to hazardous situations such as fires or explosions. When the combustion safety control detects an unsafe condition, it energizes the combination gas valve, prompting it to close and thereby halting the gas flow.

In contrast, a manual gas valve requires human intervention to open or close and does not automatically respond to safety controls. A pressure relief valve is intended to release excess pressure in a system to prevent damage, rather than managing gas flow in response to safety controls. Similarly, a temperature control valve regulates the flow based on temperature settings and does not serve to shut off gas supply in reaction to combustion safety controls.