Which component isolates hydraulic pressure coming from the engine driven pump from the rest of the system when the emergency system is activated?

• A. Slide valve
• B. Firewall shutoff handle
• C. 3500 psi pressure relief valve
• D. Reservoir piston

Answer: (A)

During an emergency, hydraulic power must be kept separate so the emergency circuit can operate reliably without interference from the normal engine-driven pump. The slide valve is the component that moves to block the engine-driven pump’s connections to the rest of the system and route flow only to the emergency circuit. This isolation prevents cross-flow and ensures the emergency hydraulic functions get power when needed. The firewall shutoff handle is for shutting off engine flow in a fire or maintenance situation, not the emergency isolation. A 3500 psi relief valve protects against overpressure, not isolation, and the reservoir piston relates to reservoir pressure rather than isolating the pump from the system.