I’ve got a used riello ups recently and it was not working since the beginning. The UPS was switching to batteries most of the time, but sometimes it just don’t switch to batteries and makes a continuous beep (riello manual tells that it’s a UPS fault anything except an overload).

I left it 2 weeks without using it. But know it won’t start at all. Don’t have the materials to test components for now but what are your ideas? (Even when plugged in the wall it wouldn’t start)

Maybe batteries or faulty ups

Thx