Commercial Sensor Faucet Won’t Turn On: What to Check First
When a commercial sensor faucet will not run, separate the problem into sensing, power, water supply, and solenoid operation. Many easy fixes involve batteries, a dirty sensor window, closed stops, a clogged aerator, or a model-specific reset.
Last reviewed 2026-09-12 · General facility-maintenance information, not a substitute for site procedures, manufacturer instructions, codes, or qualified professional judgment.
Safety boundary
Symptom → cause → first move
No light/no water
Check: No power or dead batteries
First move: Replace batteries or verify power.
Sensor reacts/no water
Check: Closed stop, aerator, solenoid
First move: Verify water and clean aerator.
Intermittent operation
Check: Weak power or false sensing
First move: Replace batteries and inspect sensor.
Weak flow
Check: Aerator or stop restriction
First move: Clean aerator; verify stops.
Will not shut off
Check: Solenoid debris or sensing fault
First move: Isolate water; follow manufacturer reset.
What to check first
Bring these
- Soft cloth
- Screwdriver set
- Fresh specified batteries
- Flashlight
- Small adjustable wrench
Before touching anything
- Confirm the exact location and complaint.
- Photograph labels, settings, and error codes before changing anything.
- Know how to isolate water, power, or the affected area if needed.
- Follow site-specific PPE, lockout/tagout, ladder, roof, and access procedures.
Step-by-step procedure
- 1Identify faucet and power typeFind manufacturer/model and whether it uses batteries, transformer, or plug-in power.
- 2Clean the sensor windowUse a soft damp cloth; remove soap film and residue.
- 3Check batteries or powerReplace all batteries as a set and reseat connectors.
- 4Verify supply stopsCheck hot/cold or tempered-water stops are open.
- 5Check the aeratorIf sensing works but flow is weak, remove and rinse the aerator.
- 6Use the exact reset procedureFollow the manufacturer instructions for that model.
- 7Test several cyclesConfirm consistent start, flow, and shutoff.
Stop and call a licensed professional when
- Water will not shut off and cannot be isolated
- Wiring is damaged or wet
- Hardwired power work is required
- Valve body is leaking
- Correct batteries/reset do not restore operation
Common mistakes
- Replacing the solenoid before checking batteries
- Using abrasive cleaner on the sensor
- Mixing old/new batteries
- Ignoring supply stops
- Guessing at reset sequences
FAQ
Why does it blink but not run?
The electronics may be sensing correctly while the water supply or solenoid is not responding.
Can a dirty aerator mimic failure?
Yes; restricted flow can make the faucet appear not to work.
Replace one battery or all?
Replace the full set with matching fresh batteries.
Can reflections affect sensors?
Yes, but power and water-supply checks should come first.