What keeps a solenoid type fuel gas valve closed?

A solenoid type fuel gas valve is an electromechanical device that operates by using an electric current to activate the solenoid. However, the actual mechanism that keeps the valve closed in the absence of electric power is essential to understanding its function.

In this case, the correct answer emphasizes the role of fuel pressure. When the fuel gas pressure is present, it can exert force on the valve mechanism to keep it closed, preventing gas from flowing through the valve when it is not intended to be open. This is particularly important for safety, as it ensures that the system does not leak gas in the event of a power failure or when the solenoid is de-energized.

The electric current is necessary to open the valve, as it energizes the solenoid to lift or move the valve component away from its seat. However, without fuel pressure, the valve could not remain securely closed if only dependent on the electric current. Thus, while the electric current is crucial for operation and control, fuel pressure is key to maintaining the valve's closed position when the system is not operational.