UPS systems can be very noisy. Inside the UPS there are fans running, internal components produce a very high pitch whistle while in operation, and contactors can have a large, loud, “CLUNK” when they operate. All of these are very normal sounds. If there is a concern about a sound being produced by the UPS, it would be wise to have it checked. It’s likely a normal noise that is just being noticed, but it may also indicate a failing component. Please contact one of our sales engineers to find out more information.
Check that protected equipment is being backed up by the UPS and not utility power. If it is plugged into the UPS, it is most likely a battery issue that could require replacement or there could be a major problem with your UPS. Call for service.
Look at the display and take a picture and contact your sales engineer or our main line for service.