What type of signal must be actuated by manifolds for gas cylinders during a changeover?

The type of signal that must be actuated by manifolds for gas cylinders during a changeover is a local signal. Local signals are typically used in medical gas systems to indicate an event or condition that requires attention in the immediate vicinity where the manifold operates, such as when switching from one gas cylinder to another.

This signal serves to inform personnel onsite of the status of the gas supply and alerts them that a changeover is taking place. It's crucial for maintaining the flow of medical gas without interruption and ensuring that the system functions safely and effectively.

In the context of medical gas systems, a local signal is designed to optimize responses and enhance vigilance in monitoring gas supplies, thereby contributing to a safer environment for both patients and healthcare providers. The other types of signals mentioned (emergency, warning, and main system signals) serve different purposes, often related to broader system failures or emergencies rather than the local operational requirements of cylinder changeovers.