SUVTP15KH2B4S -error fault. ''system not synchronized to bypass''

[BillP]

UNIT MODEL: SUVTP15KH2B2S

*The unit was installed in 2009 and been working very well ever since , on Monday morning this week the unit was found off showing on screen ‘’ site wiring fault’’
* We Interchanged the blue and yellow phases, the error went off but still it could not turn load on, showing ‘’load could not turn on due to weak batteries’’.
We replaced with healthy batteries, unit was able turn load on, but reporting an error ‘’system not synchronized to bypass’’ failed to go off
*Restarted the machine 3times , checke the input voltage PH-PH=400V , N-PH=231V .
* Set the Nominal UPS voltage at 400V and frequency at 50Hz.
* Still error fault ''system not synchronized to bypass’’ does exist.

Kindly Advise.

[upsguy_apc]

What caused your phase rotation to reverse? Is there a seprrate bypass input to this UPS?

[BillP]

Hello upsguy, Thanks for the response. Yes there is separrate byps.

[upsguy_apc · Accepted solution]

You should make sure the input and bypass are in phase. This should help out with your problem.