Back-UPS RS 1500 Fan Cycling

[Anonymous user]

Recently the exhaust fan on my Back-UPS 1500 seems to be periodically turning on/off even though it's not on battery.  The unit cycles even in an air-conditioned environment and there are no errors or a low-battery indicator on the LCD panel.  Any ideas what might be going on?

[BillP]

Hi Clinton,

The fan may come on for other reasons. It could be if the UPS is using its Boost/Trim function as part of Automatic Voltage Regulation, for example.

How long does it stay on when it is on? Can you possibly get a picture of the front LCD panel when the fan is operating? That can tell us what the UPS is doing at that time to maybe understand better why the fan may be running periodically.

[Anonymous user]

I'm having the same issue.  Mine just started cycling on and off.  I've had the same cpu and monitors plugged in the whole time.  This used to happen on a smaller unit but I was told that there is a threshold below the rated capacity where this happens, but this shouldn't be the case now.  Ideas???

[BillP · Accepted solution]

I would suggest providing the same information I asked the original poster to see if we can figure out why the fan is coming on when you're not expecting it.

[Anonymous user · Accepted solution]

Two of seven Back-UPS RS 1500G UPS units, all purchased within a few months of each other, have begun to run the fans all the time. 

Load never changed for months of usage, and the load was always minimal below 200W. Temperature has always been stable 24x7 at about 70F. Humidity is low and stable. 

The information for one of the two UPS units is as follows:

Model: Back-UPS RS 1500G
Serial number: 4B1539P10279
Firmware revision: 865.L5.D
Software version: PowerChute Personal Edition 3.0.2
Date of last manual self-test: 1/9/2017
Result of last manual self-test: Passed