Dehumidifier or humidifier makes loud rattling or grinding noises during operation.

Safety: Unplug the unit before tightening or adjusting components.

Steps:

• Identify noise source: Run the unit briefly with covers on and listen to locate whether the noise is from the fan area or compressor area.
• Inspect fan assembly: Remove the cover and check that the fan wheel is firmly attached to the motor shaft. Tighten the set screw if present.
• Check for debris: Remove any foreign objects contacting the fan blades.
• Compressor mounts: Verify that the rubber mounts and bolts holding the compressor are intact and tight.
• Secure panels: Tighten any loose screws on the cabinet and add foam tape where metal panels vibrate against each other.
• Replace noisy motor: If the fan motor bearings are worn and noisy, replace the fan motor assembly.