You are called to service a wall-mounted sensor faucet in a commercial washroom. The faucet intermittently dispenses water or fails to activate entirely. After checking the power supply (battery/transformer), what is the most probable cause of this issue, and what should be your next troubleshooting step?

Question: You are called to service a wall-mounted sensor faucet in a commercial washroom. The faucet intermittently dispenses water or fails to activate entirely. After checking the power supply (battery/transformer), what is the most probable cause of this issue, and what should be your next troubleshooting step?

Answer options:

• A clogged aerator; clean or replace the aerator. ✅ A faulty solenoid valve or obstructed sensor eye; clean the sensor eye and check solenoid wiring/function.
• A worn ceramic cartridge; replace the cartridge assembly.
• Excessive water pressure; install a pressure reducing valve.

Correct answer: A faulty solenoid valve or obstructed sensor eye; clean the sensor eye and check solenoid wiring/function.

Explanation: Intermittent or non-activation of a sensor faucet, after confirming power supply, strongly points to an issue with the sensor's ability to detect presence or the solenoid valve's ability to open/close. Cleaning the sensor eye and inspecting the solenoid valve are critical troubleshooting steps. A clogged aerator would affect flow but not activation, a ceramic cartridge is typically found in manual faucets, and excessive water pressure would likely cause continuous flow or leakage, not intermittent operation.