Two SMX3000RMLV2U UPS's shutdown at the same time. POSITIVE DC BUS SHORT HARDWARE CIRCUIT ERROR

[BillP]

Hello all, I was out at a customer site they were reporting that their entire IT equipment rack was dead. Arrived on site and noticed both UPS were flashing "Fault State: PFC" and  "Contact APC support" on the screens. The console in the event log showed POSITIVE DC BUS SHORT HARDWARE CIRCUIT ERROR. We unplugged the load, powered both units back on, and started the servers... everything came up fine. We flipped breakers off to both units, testing under load, and still fine. 

We spent thousands on redundant circuits, UPS, etc., yet both units died at the same time?  Units are not yet 3 years old.

We have 5% load on each unit.  Both are SMX3000RMLV2U purchased and installed at the same time.  Both have 1 external battery pack connected.

This event happened when the building lost power briefly for around 6 seconds.  There are other smaller 1500 and 2000VA units in this building and they were all fine.

[BillP]

Hi Nicholas - 

Sorry to hear about your issue. Can I ask what exactly is plugged into these units? Is there anything with dual power supplies? 

Liam

[BillP]

Yes sir - there is Cisco Switches, HP servers and some Synology Servers and some power bricks for POE from Cisco.

The Servers all have redundant power supplies and switches.

[BillP]

The issue may be caused by transients from the utility source or possibly the dual cord power supplies backfeeding during transfer. If you change your configuration so that both cords from each power supply are plugged into the same UPS you may improve performance. 

[BillP]

You were the first person to tell us this, we have called support several times and they were not able to tell us this we worked with APC when we first ordered these units and we told them that we were using them for... Can APC issue a replacement for a different model since these are still under warranty? 

[BillP]

APC wants to replace the units we have today with the same units and says its a internal issue. Does this sound right or should I push for the different units? I don't want this to happen again.

[BillP]

Case # 58669052

[BillP]

Hi Nicholas - 

If you plug the power cords into a single UPS, you should not have an issue using the same model. Alternately, if you do decide to continue plugging into two separate units you could try disabling Green Mode via the LCD screen, which should improve your performance. 

Liam

[BillP]

Green mode is off - also it doesn't say anywhere in APC guides about this. Please replace the unit with the one you recommended.

[BillP]

Hi Nicholas - 

Tech support can assist you with a warranty replacement. I believe you said you already opened a case. 

Liam

[BillP]

They sent the SMX series. Can you help them get the right series?

[BillP · Accepted solution]

Hi Nicholas - Sending you an email to assist...