What position must the system be in to indicate readiness for operation?

The service position is the correct answer because it refers to the specific state in which a water treatment or filtration system is fully prepared for operation. When the system is in the service position, it indicates that all necessary parameters are met, including proper configuration, pressure settings, and flow rates, allowing the system to commence its function of treating water effectively. This position ensures that the components such as valves, filters, and other critical parts are engaged correctly, which is essential for optimal performance.

In contrast, the initial position typically indicates that the system has just been set up but may not yet be fully operational. The test cycle refers to a phase used primarily for diagnostic purposes, where the system is run to verify its functions rather than actively treating water. Standby mode indicates that the system is on but not currently engaged in processing water, which does not represent a readiness for operation. Thus, being in the service position is vital for confirming that the system is ready to perform its intended function reliably.