My Back-UPS emits a clicking sound, yet functions properly.
Back-UPS and Back-UPS PRO
The relay inside the UPS may be audible in some environments. The relay switches when Intelligent Battery Management features such as Boost and Trim are initiated and when the UPS switches to battery. This is proper operation of the UPS.
Boost and Trim are Automatic Voltage Regulation features where the UPS will either boost or trim the power to protect brownout or overvoltage conditions respectively. Boost or Trim can last as long or short as the brownout or overvoltage condition will last. If the clicking becomes frequent, there may be issues with incoming power. Please contact techical support for further assistance.