Problem with Eaton Powerware 9120 UPS System, comming "Site fault" with bip alarm code

SOURCE: My UPS shows 'site fault"

battery show 12v but no backup

SOURCE: site fault

If UPS is displaying "Site Fault", it is doing its job correctly. Yoiu need to check the wall receptacle. Probably hot and neutral reversed by whom ever installed the wall receptacle.

SOURCE: hi we have problem with 6kva 9120 eaton ups,

The Poweware UPS is a true on-line UPS System, so it will handle sustained over and under voltages to +20% and -15%. If you are getting input spikes, the UPS has MOV's which will handle input spikes, and if too great a spike, the MOV will die attempting to save the UPS output load. If you are having further UPS input problems you need to put a good quality surge arrestor at the panel feeding the UPS on BOTH circuit legs feeding the UPS.