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Part 3: UPS Maintenance Checklist
By Michael Newbury
August 2008 -
Power & Communication
For a more recent article on UPS maintenance, go to
Regular equipment testing should be part of a facility’s UPS maintenance schedule. Such a schedule might include the following elements:
• Visually inspect equipment for loose connections, burned insulation or any other signs of wear.
• Visually check for liquid contamination from batteries and capacitors.
• Clean and vacuum UPS equipment enclosures.
• Check HVAC equipment and performance related to temperature and humidity.
• Conduct thermal scans on electrical connections to ensure all are tight and not generating heat, which is the first and sometimes only indication of a problem. A non-evasive diagnostic tool helps technicians identify hot spots invisible to the human eye. Technicians should retorque if thermal scan provides evidence of a loose connection.
• Provide a complete operational test of the system, including a monitored battery-rundown test to determine if any battery strings or cells are near the end of their useful lives.
• Test UPS transfer switches, circuit breakers and maintenance bypasses.
If a generator is part of the building’s emergency-power system and feeds the UPS, it also will need to be tested monthly or quarterly. Most facilities have a generator-maintenance schedule in place in which testing frequency is defined.
A UPS typically is sized to carry the load for a short period of time. Longer outages require backup-power generation to maintain critical services. Each facility is unique, and managers need to develop a maintenance schedule to suit each site’s specific needs.
Keeping UPS Up and Running
Part 1: UPS: Preventive Maintenance Ensures Power Supply
Part 2: UPS Testing: Identify Potential Power Interruptions
Part 4: Top Tools for UPS Maintenance
Part 5: Adhere to NFPA Requirements During UPS Testing