Like most electronic devices, DVRs and NVRs have a fan inside them to prevent the unit from overheating and damaging the motherboard. All DVRs / NVRs exhibit minor noise from fan operation.
To troubleshoot excessive fan noise:
To access and clean the fan:
Power off the DVR / NVR system and unplug all cables.
WARNING: Make sure that the system is off and the power cable is disconnected before attempting to open your DVR / NVR.
The DVR / NVR cover is secured with screws. Remove the screws and slide the cover off.
WARNING: The inner casing of the DVR / NVR has sharp edges that can lead to injury if not carefully handled. Be careful not to let any tools or loose parts touch sensitive components such as the circuit board.
Clean the fan using a compressed air can or a vacuum if necessary.
Carefully replace the casing of the DVR / NVR and secure the screws.
Reconnect the power source and monitor.
If the fan is still excessively loud, contact Technical Support.