Symmetra RM dropping load coming out of bypass

[JB_68_apc]

This was originally posted on APC forums on 12/22/2014

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I just can't seem to solve this one. Symmetra RM kicked on to battery backup during a recent power outage. All systems were shut down gracefully, and the UPS was powered off to silence alarms, and as we knew the outage would be an extended one.

Power was restored the following day, but the Symmetra refused to power up until I put it into Bypass using the breaker on the rear. That brought the UPS up, but obviously in Bypass mode, with the amber light on the LED panel indicating such. All my attempts to power up attached equipment fail when I take the unit out of Bypass mode with the breaker on the rear. Attached equipment works fine while in Bypass, but I lose all power to attached equipment as soon as a flip the breaker out of Bypass (although the LED panel remains fully functional).

Using the LED panel to bring the system out of Bypass when it's in this limbo state is not successful.

Power modules show as 'Off and OK' when in breaker-induced Bypass, and 'On and OK' when in the limbo state (when Bypass breaker is in the 'Out of Bypass' position, i.e. when there is no output)

LED shows Charge 99%, Load 35%, Voltage 239V in 240V out (60 Hz), runtime 22 minutes.

So, I'm stuck in a state where a 1 second power interruption (frequent in my area) brings my entire rack down.

Any thoughts or ideas?

Thanks.

[BillP]

This reply was originally posted by Jordan on APC forums on 12/23/2014

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Hi Jeremy,

I would strongly advise calling into Single Phase Symmetra Technical Support for an issue like this.  Aside from the "Load On" and "Bypass" LED indicators, is there a fault indicator lit?  What are the LED light patterns on the intelligence modules?  What are the states of your batteries aside from having a charge of 99% (this is a big reason a unit may not transfer to online operation - specifically battery bus voltage, age, temperature)?  Have any of the power modules or intelligence modules been replaced?  This is a complex issue that I once again advise calling into APC about to receive full support and come to an issue resolution.

Regards,

[JB_68_apc]

This was originally posted on APC forums on 1/22/2015

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Thanks for the response, sorry for my slow reply.

No fault indicator lights on.

Battery modules are approximately 18 months old. Reported battery voltages are 120.0V Nominal and 138.1V Actual. Showing 2 Batteries, 0 Bad.

Showing 3 Power Modules, 0 Bad.

Intelligence Module showing all green.

[BillP]

This reply was originally posted by Jordan on APC forums on 1/23/2015

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Hi Jeremy,

Have you increased your load on the RM at all (ie. attached more equipment to the unit that could be overloading the unit when it tries to run online and commands the unit to drop the load rather than return to bypass)?

What is the setting you have on the RM under the menus "Setup -> Bypass"?  There are two options, "go to bypass" and "drop load". 

[JB_68_apc]

This was originally posted on APC forums on 1/27/2015

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No change in load, sitting at 33%.

Setting is 'Go to bypass'.

I did have a lengthy call with support, and they are at a loss as to why it's not working. Someone senior is supposed to be getting back to me in the coming days.

Thanks again.

[JB_68_apc · Accepted solution]

Old topic, but thought I'd share the solution anyway.

Despite the fact there were no meaningful messages, it was the Main Intelligence Module. I rolled the dice and picked one up and the problem was solved. Very odd the the redundant Intelligence Module didn't take over, as it also tested as OK. I went ahead and replace that too.