APC Smart-UPS 2 space rackmount UPS

[losrangeros]

My APC Smart-UPS 2 space rackmount UPS's fan is always on. It is on Very low and is Very quiet, but it's always running, almost silently.  Is there  some kind of calibration to get it to shut down? I notice there's a 'sensitivity' adjustment  and a dim green LED on the back. 

Is it dangerous for the fan to always be on?

Thanks.

[Teken]

There is no calibration for the user to adjust the UPS's fan speed or state (On/Off). One would think in 2023 that such a large company would have adopted a PWM fan as seen on millions of other appliances?!? Every device has an operational life span based on MTBF (Mean Time Between Failure). One would assume APC has selected a fan that has a MTBF of ten years or more.

Regardless, the fan is intended to run 24.7.365 to keep the internal system cool. The only thing you can and should do is ensure that the room is clean and dust free. This will insure the fan doesn't become caked and covered in dirt which will impact its service life.

The sensitivity adjustment on the rear I believe is to adjust the UPS to the type of power quality in your environment. If the unit is set to the most sensistive the UPS will transfer to battery more often to ensure the connected loads are provided clean power. While the selecting a less sensitive setting will allow the UPS to accept poor (VAC) quality into the UPS and connected load.

It should be noted a more sensitive setting will cause the UPS to activate (Transfer) its relays more often. In doing so it will cause the relays to wear out faster and potentially set you up for the all too famous *Relay Weld* failure!