What should an uninterruptible power supply (UPS) preventative maintenance contract service include?

Having a preventative maintenance contract in place is essential to ensure that the UPS unit undergoes planned and regular servicing and controlled firmware upgrades at least twice a year.

Such services allow the technician to:

1. Perform a visual inspection for any possible signs of component wear and tear, which may be signs of something starting to fail.
2. Check the necessary fine adjustments to ensure that the unit – particularly the inverter power supply quality feeding the critical load – is optimised for performances and efficiencies.

Optionally, the following can assist in preventing and detecting minor problems from becoming catastrophic: additional testing such as Infrared imaging to look for “hot spots”, and battery impedance testing to determine the performance and service life state of a VRLA Sealed lead-acid battery.

• Batteries and capacitors should be checked for any signs of leakage, corrosion, and ripple voltage measurements must be taken.
• Mechanical checks and tightness of connections should be checked.
• Fans should be checked for good airflow.
• General site cleanliness should be monitored and dust removed from the UPS.
• Event history and software logs should be downloaded and firmware upgraded to the latest version.

After each service, the software download will be analysed to see if any problems are arising that were not present at the time of the on-site service. Whether site-related or product-related, a service report with recommendations can then be sent to the uninterruptible power supply user.