APC UTS10BI Sys Fault Condition - Communication Error

[Anonymous user]

I turned on my APC UTS10BI transfer switch from the main breaker panel.  A few minutes later the unit began clicking on and off and displayed the message, "SYS Fault Condition Communication Error.  Try Recycling Power or call 800-800-4272"  I have turned the main breaker at the panel on and off several times and continue to receive the same message.  Any assistance is GREATLY appreciated.  The unit was installed by an electrician and I know little (to nothing) about electric.

[Anonymous user]

I experienced similar symptoms but it was caused by a circuit overload which both tripped a breaker on my main panel and blew a fuse in the UTS. This may not be your cause but your electrician shuld remove the cover plate and check the UTS' fuses.

[BillP]

Hi 

Sounds like an issue with the daughter board which houses the intelligence. However, I've never known of the daughter board to fail. How long it's been installed?

[Anonymous user]

Bill, Thanks for the response.  It was installed in 2011 when I purchased a Honda EU6500w generator.  The power flickered briefly as we have a company trimming trees for our local BGE (Gas & Electric) company.  The issue seemed to coincide with the brief power interruption.  I replaced fuses 9 & 10, but the issue still remained.  I tested the other fuses and they were hot.  My electrician installed a dedicated breaker in my main electric panel for the APC transfer switch.  Do you think the breaker in the main panel may have failed? 

Before the unit was installed, we never tripped a breaker at the main panel.  After the APC was installed, we had numerous blown fuses in the APC unit when my wife would use her hairdryer upstairs.  I switched out all of the 15 amp fuses for 20 amp and that seemed to resolve the issue.  A master electrician who installed the unit advised that the circuit with the hair dryer was not overloaded.  Do you think a manual transfer switch would be a better choice for my situation?  Is it OK to have all 20 amp fuses in the APC?  I configured the APC for each circuit to reflect a 20 amp fuse.

If it is the "daughter board" can it be fixed or is it cost prohibitive?

Thanks again for your assistance.

[wayne_i_apc]

Do you have a UPS connected to the (IEC) "UPS Inlet" on the front of your UTS? If so, you also need to turn it off when you turn off the Main Panel breaker to achieve a "hard" reset of the UTS.

I hope it was a poor choice of words when you said "I tested the other fuses and they were hot". When you are diagnosing a problem there is the potential for a component to be PHYSICALLY hot, which could indicate some VERY serious problems!

Since APC specifies 20 amp fuses may be used, the UTS will be OK with them provided they match the type recommended by APC in the documentation. Since the APC recommended fuse is a "fast blow" type, it is more susceptible to surges like a hairdryer turning on, and others have reported blown UTS fuses resulting from burning-out nightlight bulbs. While a properly sized circuit breaker in your main panel is the best protection for the circuit when on utility power, the fuse internal to the UTS (although acting as secondary protection on utility power) becomes the primary overload protection for the circuit when operating on a backup source such as a generator. This means that if the circuit breaker is rated at 15 amps and you use a 20 amp fuse in the UTS, you could possibly overload the 15 amp wiring in your home without blowing the 20 amp fuse while operating on a generator. I don't know if having the UTS Circuit Setup configured for 15 amps will result the UTS shutting off the circuit when the load reaches that level.

As Bill has suggested, the diagnostic message "Communication Error" implies that the problem is more involved than bad fuses. Since APC considers the fuses to be the only "field" or user replaceable parts, the question may be does the same organization that APC recommends for UPS repairs also work on it's UTS products?

[Anonymous user]

Wayne,  Thanks so much for the detailed response.  No UPS is connected to the front inlet.  Hard reset has been tried multiple times without success.  As stated previously, my experience with electricity is limited.  It was a poor choice of words.  Perhaps "energized" would have been a better selection (not hot as an temperature).

I did purchase the recommended 20/15 amp fuses as specified by APC.  In my opinion the overly sensitive nature of the fuses, coupled with the cost and inconvenience  to replace each one, is a design flaw.  If a low wattage "night light" causes a fuse to blow, the APC "engineers" need to revisit the configuration of this unit.  I never had a power issue (or tripped breaker) before installation of this APC.  I purchased the APC to work in conjunction with a Honda EU6500is portable generator for an occasional power outage.  Unfortunately, the APC has become the problem.  Replacing the 15amp with a 20 amp fuse did resolve the tripping breaker.  

You indicated that the APC is the "primary overload protection" when operating as a back-up source such as a generator.  If that is the case why does it blow fuses when the unit is not activated (turned off at the main breaker panel).  Would there be a way to make the unit passive until turned on at the main breaker panel so power does not cycle through it until needed OR replace the problematic fuses with a breaker type system?

A master electrician checked the panel and indicated that even if I changed the 20 amp fuses in the APC, the main panel breaker would still trip in an overload situation, which has not happened since the fuse upgrade.  My wife's hair dryer no longer blows a fuse.

Overall, a poorly designed unit.  Good in theory, but an engineering failure by APC.  I have decided to trash the APC UTS and replace with a manual transfer switch.  If anyone out there wants about 12 (20) amp fuses and (10) 15 amp fuses please let me know.  They are expensive so they will be removed before I toss this thing in the garbage. Now I am beginning to wonder about the potential design flaws in my APC computer back-up system???

Thanks again for the information.   

On 5/2/2016 12:43 AM, Wayne said:

Since the APC recommended fuse is a "fast blow" type, it is more susceptible to surges like a hairdryer turning on, and others have reported blown UTS fuses resulting from burning-out nightlight bulbs.

While a properly sized circuit breaker in your main panel is the best protection for the circuit when on utility power, the fuse internal to the UTS (although acting as secondary protection on utility power) becomes the primary overload protection for the circuit when operating on a backup source such as a generator. This means that if the circuit breaker is rated at 15 amps and you use a 20 amp fuse in the UTS, you could possibly overload the 15 amp wiring in your home without blowing the 20 amp fuse while operating on a generator. I don't know if having the UTS Circuit Setup configured for 15 amps will result the UTS shutting off the circuit when the load reaches that level.

[Anonymous user]

Robert,  Thanks for your response.  Unfortunately, I have become intimately familiar with the replacement process due to numerous blown fuses.  Both the breaker and fuses have been tested.  Thanks again for your suggestion.

[wayne_i_apc]

On 5/2/2016 8:17 AM, Brian said:

In my opinion the overly sensitive nature of the fuses, coupled with the cost and inconvenience  to replace each one, is a design flaw.

I agree that a more robust and convenient overload protection system than internal fuses would be a big improvement. It will have an impact on the cosmetics and manufacturing of the unit, e.g. either having circuit breakers protruding from the front panel, or adding an access panel that's easier to open than removing 6 screws and lifting off the whole front cover.

On 5/2/2016 8:17 AM, Brian said:

...why does it blow fuses when the unit is not activated (turned off at the main breaker panel).  Would there be a way to make the unit passive until turned on at the main breaker panel so power does not cycle through it until needed...

The nature of ANY transfer switch-- to allow the selection of one power source to be directed to a load while isolating the unselected sources from each other and the load-- requires power to pass through the transfer switch when the load is powered by any source, be it utility or generator. The most effective protection (fuses or otherwise), in terms of protecting both the load circuit and the transfer switch, would be placed closest to the point where the power leaves the transfer switch to the load wiring. This means the load current will always pass through the transfer switch fuse, whether on utility or generator power. And as you have noticed, when utility power is turned off to only circuits 9 and 10 for a UTS10BI and no backup power is provided to the UTS, the "brain" of the UTS is turned off but utility power continues to pass through circuits 1 through 8 with the potential to blow one of the fuses.

On 5/2/2016 8:17 AM, Brian said:

...even if I changed the 20 amp fuses in the APC, the main panel breaker would still trip in an overload situation, which has not happened since the fuse upgrade.  My wife's hair dryer no longer blows a fuse.

If your main panel breaker for the circuit in question is rated at 15 amps (and presumably the wiring is also rated at 15 amps) then it should provide appropriate overload protection for the circuit WHEN ON UTILITY POWER even if you have installed a 20 amp fuse in the UTS. However, WHEN ON BACKUP POWER / GENERATOR the 20 amp fuse in the UTS could allow 20 amps (or possibly a bit more) to pass for an indefinite time into the 15 amp rated wiring. That should not happen unless you were to decide to plug something in thinking "I want to use this (vacuum cleaner?), I can plug it in HERE and run it off the generator at the same time as all the other 'regular' things!" If that were to happen it could be CATASTROPHIC! Your description also leaves me to ask, did your main panel circuit breaker trip at the same time a fuse in the UTS blew since you say it hasn't happened since changing to 20 amp fuses? I would find that hard to explain!

On 5/2/2016 8:17 AM, Brian said:

I have decided to trash the APC UTS and replace with a manual transfer switch.

Like you, I am an APC user, with no other association to APC, but after the investment has already been made (and assuming you can fix the problem causing the error message, have you checked the ribbon cables between the main board and the daughter board? Be CAREFUL inside the UTS-- LETHAL VOLTAGES PRESENT! ), would encourage you to consider the advanced features that the UTS provides that aren't possible with a manual transfer switch, most significantly, load management that can automatically turn off low priority loads if your generator approaches an overload condition. I think it would be great to see APC use some of this feedback for an updated or "next generation" UTS since it seems like it has not been given much apparent follow-up by engineering since it's original release, especially compared to the spectrum of UPS and ATS products by APC.

Best of luck to you with your choice!

[Anonymous user · Accepted solution]

Wayne,  Thanks again for your invaluable advice.  After trying to power cycle the APC several times without success (and cutting all power from the main panel) I opened the APC front panel.  I used my voltage tester and did not get a reading from fuses 9 & 10; although the breaker that powers the APC UTS in the main panel was on.  Tried new 20 amp fuses and still no reading.  Called APC tech support and their suggestions did not work.  Here is the strange part...I detached the wires that connected to circuits 9 & 10 inside the APC, pushed them back in, and now the APC works fine.  Even connected the generator and did multiple power cycles and it all works perfectly.   The voltage tester is now showing that 9 and 10 have power.  Do you think somehow the wire(s) were fused during the brief power surge or were simply loose.  Happy to say I will keep the unit for now and save some $$$.  Your insights are appreciated...