Brain Dead

[Anonymous user]

Hi,

I've seen the procedure to make a smart ups "Brain Dead". What features are disabled/enabled when in a brain dead mode and is there a procedure to put it back into "Smart" mode?

Chris

[BillP]

yes, you're right. that is most likely the only way to stop the fan. what model is it by the way?

[Anonymous user]

Here's the problem that i'm having with my ups. The fan is on... ALWAYS...

I can un plug the ups, i turn it off, remove the load... it's always running. The only way I can shut the fan off (low mode) is to disconned the battery.

It sounds like performing the "brain dead" operation will shut off the fan, however that may be annoying over time since I'll most likely be turning it off each night. My computer is in my office/bedroom, so it's making noise when I sleep.

Chris

[BillP]

the braindeading of the UPS just discharges the UPS's capacitors of all DC voltage. so at this point the UPS will be turned off (including the output power to your load) and completely inoperable.

when you turn it back on, it will automatically be in smart signaling mode and you don't have to do anything to it.

this procedure resets effectively clears the communication bus since there will be no more voltage on the bus to keep any settings, etc

[Anonymous user]

It's an SUA 1000xl...

[Erasmus_apc · Accepted solution]

Later SUA units will always have their fan on "low-speed", unless the UPS is unplugged and brain-deaded.

The fans will only come on high-speed if the unit is charging the battery, on battery, the load is over 75%, or if the temperature goes above 40 degrees C.