Key Takeaways
Clean the sensor lens first. This fixes most cases of a hand dryer sensor not working.
Check hand placement and sensor range before assuming the unit is broken.
Test the power supply, wiring, and control board if cleaning doesn't fix it.
Follow a maintenance schedule to prevent most sensor problems.
Call a technician if the control board or motor is at fault.
Introduction
Why is my hand dryer sensor not working? You wave your hands under the unit, and nothing happens.
Follow this guide to diagnose and fix the problem yourself. A commercial hand dryer uses touchless technology and an infrared sensor to detect motion. When the sensor gets dirty, misaligned, or loses power, the unit stops responding. Use the steps below to find the cause, apply the fix, and stop the problem from coming back.
Step 1: Learn How a Commercial Hand Dryer Sensor Works
Before troubleshooting, get familiar with how the parts work together. A commercial hand dryer uses an infrared sensor or proximity sensor to detect movement. When your hands break the beam, the sensor signals the control board. The control board then powers the motor and starts airflow.
Locate the sensor lens behind the small clear cover on the unit. Check this cover first. Dust, soap residue, or water spots block the signal path. Next, check the sensor range. Most touchless hand dryers detect hands within a few inches, not farther back. Test at this distance to rule out range as the issue.
Step 2: Diagnose Why Your Hand Dryer Sensor Is Not Detecting Hands
Work through this checklist to find the cause:
Check the sensor lens for dirt. Soap film or grime blocks the infrared beam.
Check your hand position. Hands placed too far or at the wrong angle miss the sensor range.
Check the wiring. A loose or damaged connection interrupts the signal.
Check the power supply. A tripped circuit breaker cuts power entirely.
Check the lens for damage. Cracks or scratches scatter the infrared beam.
Check the control board. A failed board can't process the sensor signal, so the motor never starts.
Check for thermal shutdown. Thermal overload protection shuts some units down after overheating, which can mimic a sensor fault.
Run through this list first in high-traffic restrooms, where units work harder and collect grime faster.
Step 3: Follow This Hand Dryer Sensor Troubleshooting Checklist
Complete these steps in order.
Check the power source. Confirm the unit is wired correctly and check the circuit breaker.
Wipe the sensor lens. Use a soft, dry cloth. Skip harsh chemicals.
Test hand placement. Hold your hands directly under the sensor, two to four inches away.
Remove obstructions. Take down stickers or signage placed too close to the sensor.
Inspect the wiring. Check for loose connections near the sensor housing.
Reset the unit. Cut power for a minute, then restore it.
If these steps don't fix it, move to Step 4 to match the exact symptom to its cause.
Step 4: Match Your Symptom to the Right Fix
Use this table to identify your symptom and apply the fix.
Step 5: Set Up Preventive Maintenance
Follow these steps to prevent the sensor problem from returning:
Clean the sensor lens weekly in high-traffic restrooms.
Check the air intake and HEPA filter for buildup. A clogged filter strains the motor and triggers thermal protection.
Keep sprays and air fresheners away from the unit to stop residue from reaching the lens.
Schedule a full inspection twice a year, covering wiring and the control board.
Keeping the restroom clean around the unit also helps, since less grime nearby means less reaching the sensor. See our guide on hand dryer maintenance tips for more steps facility teams often skip.
Step 6: Decide Whether to Repair or Replace the Sensor
Stop here if cleaning and troubleshooting fixed the problem. If the sensor still won't respond, or the unit is old and parts are hard to find, replace it instead.
Check compatible parts from brands like Dyson, Excel Dryer, Bobrick, Mitsubishi Electric, World Dryer, and American Dryer. Most let you swap the sensor without replacing the whole unit. Browse Hand Dryer Parts to find one that fits.
If the whole unit needs an upgrade, check our Commercial Hand Dryers selection instead.
Confirm any replacement still meets ADA compliance requirements for restroom fixtures, particularly mounting height, if your restroom needs to meet accessibility standards.
Conclusion
These steps can help you fix a hand dryer sensor that won't detect your hands. Start with the lens, check hand placement, and confirm power. If the problem continues, check the control board and wiring next, and repair or replace the part as needed. Follow the maintenance steps in Step 5 to keep your touchless hand dryer running reliably.
FAQs
Why is my hand dryer sensor not working?
Check for a dirty lens, interrupted power supply, or loose wiring.
Why is my hand dryer not detecting my hands?
Move your hands closer to the sensor, and check the lens for residue.
How do I clean a commercial hand dryer sensor?
Wipe the lens with a soft, dry cloth. Skip abrasive cleaners.
Can a dirty sensor stop a hand dryer from working?
Yes. Dirt blocks the infrared beam, so the unit can't detect motion.
How do I know if my hand dryer sensor is faulty?
Clean the lens and reposition your hands first. If it still won't respond, the sensor is faulty.
Can the sensor on a commercial hand dryer be replaced?
Yes. Most commercial models allow sensor replacement without a full unit swap.
Why does my touchless hand dryer activate intermittently?
Check the wiring first, then check the sensor for wear.
How often should a hand dryer sensor be cleaned?
Clean it weekly in high-traffic restrooms, monthly in lower-traffic spots.
Should I repair or replace a commercial hand dryer with sensor issues?
Repair it if basic troubleshooting fixes the problem. Replace it if problems continue or the unit is old.