Maintaining a UPS

Maintaining Your Emergency Power System (UPS)

Applies to Leibert, Emerson, and Other Systems

This webpage is going to attempt to quickly explain some best practices in maintaining an industrial size emergency power backup system. First, let’s look at the top causes of UPS failure per a survey published by Emerson in 2011 of the top causes of UPS failure:

Top causes of UPS equipment failure

  • UPS battery failure- 65%
  • UPS capacity exceeded- 53%
  • UPS equipment failure- 49%
  • Water incursion- 35%
  • Heat related/CRAC failure- 33%
  • PDU/circuit breaker failure- 33%


What can be done to prevent these things from happening? The answer is having scheduled maintenance done by qualified technicians.

  1. Make a maintenance schedule and be militant about sticking to it.
  2. Keep detailed records on what happens and what findings there are one each maintenance visit, PLUS record how often the UPS is used in a failover situation and how long that happened. This is very important to determine battery and capacitor impact.
  3. Set up a schedule of regular daily, weekly, and monthly inspections on different components, especially capacitors and batteries. Batteries need to be replaced in a 3 to 5 year window depending on usage.
  4. Keep posted contact numbers for emergency help if needed in a clear and visible place.
  5. Review with staff quarterly procedures not only for an emergency, but maintenance expectations.