What are the two conditions a pressure tank signal-initiating device must indicate?

The correct answer highlights the fundamental operations of a pressure tank signal-initiating device, which is crucial in monitoring and controlling pressure systems. The conditions indicating pressure increase and decrease are essential for ensuring the safe and efficient operation of systems that rely on pressurized tanks.

When a pressure tank's pressure rises above the set threshold, it may indicate a potential hazard such as over-pressurization, which could lead to system failures or safety hazards. Conversely, a pressure drop below a certain level may signify leaks or insufficient fluid, which could also compromise the system's functionality or safety. Therefore, continuously monitoring these two parameters allows for quick responses to maintain optimal operational conditions and to prevent accidents.

Options related to voltage and current or temperature do not specifically address the primary function of pressure monitoring in tanks. Indications of leaks and maintenance needs, while important for overall system integrity, do not directly correlate with the primary signals that a pressure tank signal-initiating device is designed to track—namely, changes in pressure. Therefore, monitoring pressure increases and decreases is the best choice for understanding the operational requirements you need to focus on in this context.