A plumber is called to service an electronic, sensor-activated faucet in a commercial washroom. The faucet intermittently dispenses water or fails to activate, despite being connected to the building's main cold water supply line. The batteries have been recently replaced. What should be the plumber's next diagnostic step?

Question: A plumber is called to service an electronic, sensor-activated faucet in a commercial washroom. The faucet intermittently dispenses water or fails to activate, despite being connected to the building's main cold water supply line. The batteries have been recently replaced. What should be the plumber's next diagnostic step?

Answer options:

• Increase the water pressure to the building. ✅ Check the sensitivity settings of the infrared sensor.
• Replace the solenoid valve.
• Inspect the aerator for blockages.

Correct answer: Check the sensitivity settings of the infrared sensor.

Explanation: Intermittent operation or failure to activate for a sensor faucet, especially after checking power (batteries), often points to an issue with the sensor itself. Adjusting or cleaning the infrared sensor's sensitivity settings is the most logical next step to ensure it is accurately detecting hand movement. Water pressure and aerator blockages would affect flow consistently, not intermittent activation, and replacing the solenoid without diagnosis is premature.