Dehumidifier shutting off while the room still feels damp, or running when it feels dry? The humidity sensor tells the unit when to work, so a dirty or faulty sensor throws the whole cycle off.
Here is how the humidity sensor works and how to fix it.
This article will teach you:
- What the sensor measures
- Why it reads wrong
- How to clean and test it
- When it has failed
Why the Sensor Misreads
- Dust on the sensor skewing readings.
- Poor placement near a draft or wall.
- A blocked sensor intake.
- A worn humidistat.
What You’ll Need
- A separate hygrometer
- A soft brush
- Your owner’s manual
How to Fix the Humidity Sensor
- Compare readings. Set a hygrometer nearby to see how far off the unit is.
- Clean the sensor. Dust the sensor and its intake gently.
- Reposition the unit. Keep it away from drafts, walls, and direct airflow.
- Recalibrate. Use the calibration option if your model has one.
Pro Tip: Place a cheap hygrometer next to the dehumidifier for a day. If the two disagree a lot, the sensor is off; if they agree, the unit is working and the room is simply drier than it feels.
When to Look a Little Deeper
Because the sensor drives cycling, it helps to check related behavior, and reviewing a unit that runs constantly, a unit not collecting water, or the frost sensor can reveal the cause.
Because sensing and moisture load connect, reviewing why a unit is drawing too much moisture or not detecting humidity changes helps confirm a sensor fault.
When to Call a Pro
If the sensor is clean and well placed but readings stay wrong, the humidistat or board has failed and needs service or replacement.
Wrapping Up
Odd cycling is usually the sensor. Here’s the recap:
- Compare against a hygrometer.
- Clean the sensor and intake.
- Reposition away from drafts.
- Recalibrate if possible.
Clean and compare first, and the cycle usually settles. You’ve got this.