SMX2200RMHV2U fans always running

[zdave]

When are the fans supposed to run? I gather from here https://www.se.com/us/en/faqs/FA156553/ that they shouldn't be running when the battery is charged, there is low load, the UPS is on mains power, and the internal temperature is low.

The fans on my unit are always running though, _except_ when on battery with no load. The internal temperature reads as ~29C and as far as I know the battery is charged (it shows as 100% charged). Is there any way to find out why the fans are running? Is the list of conditions above accurate?

[Teken]

The information stated in the APC FAQ is a high level catch all.

But as stated regarding the SMX Series this is dependent upon firmware in place and production year / hardware revision.

You’ll find some units in the field where the fan runs continuously at a low speed. Whereas some units only turn on based on the APC FAQ such as:

Charging, >75% Load, On Battery / Inverting, High Temperature >40’C.

 
In some edge cases the internal fan will come on during the AVR engagement or when it’s been in this state for an extended period of time.

NOTE: Previous UPS firmware releases have changed the way the fan behaves depending upon production year and fan installed. Some units only have a single stage output whereas others have variable fan (RPM) output based on input voltage.

There are no APC UPS that incorporate a PWM Fan.

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[zdave]

Thanks for the reply. The unit is running the latest firmware (15.0). The hardware itself is quite old -- the display says Nov 2013. The battery is new though, or at least has new cells (built by UPS-Trader in the UK).

I believe the fans are running at high speed all the time, as they're really noisy and the noise doesn't change when the load increases or when going on battery. I don't think AVR is engaging -- the display says "On Utility - Green" (or simply "On Utility" if I disable green mode, which doesn't seem to make any difference to the fan behaviour). I presume if AVR was engaging it would say something else? Is there any way to tell if the UPS thinks the battery is charging or not?

[Teken]

If the AVR circuit is engaged it will be displayed on the LCD, NMC, Power Chute, SNMP, etc. Your system is a 120 VDC nominal voltage as such the float voltage depending upon operating temperature will range from 128 ~ 129.XX VDC.

If the system is charging the output voltage will range from 136 ~ 145.XX VDC depending upon operating temperature / RBC health.

You can load the system past 75% capacity to see if the fan increase in speed. You’ll want to do this on AC Mains and without to validate how the system reacts.

NOTE: In rare cases completing a brain dead reset may help resolve the issue (IF) the unit was intended to operate in a dual stage manner vs single stage of high.

You may follow the procedure as outlined in this APC Resource Link and report back your findings:

https://www.se.com/us/en/faqs/FA156611/

Also, this would be a good time to inspect the internal compartment. If the interior is covered in dirt, dust, hair, clean it out with electronic safe compressed air. 

Insure the fan moves freely when spun by hand and clean out all the fan blades while inside. It goes without saying great care must be taken even if AC Mains & RBC are disconnected!

Do (NOT) touch anything inside especially capacitors in the charging circuit.

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[zdave]

Hmm the battery voltage shows as 135.2V.

Do you know what firmware variant should be programmed? Or does this depend on the precise HW version? I see that there are a few SMX variants available eg SMX1003, SMX20, SMX23...

[Teken]

The information you referred to is the UPS ID which is specific to when the hardware was produced for each series.

You (cannot) cross load any UPS Firmware from a different UPS ID system. Doing so will brick the system entirely so please don’t consider this.

Please call out the UPS ID from the LCD -> About, NMC -> About UPS, Power Chute, or from under the cover affixed to the MCU.

Have you completed the two action items outline above and what were the results???

IE: Brain Dead Reset / 75% Load Test

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