A UPS System is there for a reason: to keep critical equipment running when the mains supply cannot.
Yet a UPS can develop problems long before a power cut puts it to the test. Batteries deteriorate, components age, loads increase and maintenance gets postponed. In many cases, warning signs appear well before a complete failure.
Understanding the most common UPS failure reasons can help Facilities Managers, IT Managers and Operations Directors identify problems earlier, reduce downtime and keep critical infrastructure protected.
Here are eight causes we regularly see behind a UPS fault, along with practical steps that can reduce the risk.
Lack of UPS maintenance
Poor or infrequent UPS maintenance is one of the biggest risks to UPS reliability.
A UPS system contains batteries, capacitors, fans, filters and other components that deteriorate with use and age. Without planned UPS maintenance, developing problems can remain hidden until an alarm occurs or the system fails during a mains outage.
A UPS maintenance visit should assess the condition and operation of the UPS rather than simply confirm that it switches on. Battery condition, alarms, operating parameters, ventilation, load levels and signs of component deterioration all deserve attention.
UPS battery degradation
UPS batteries have a finite service life. Their condition can deteriorate because of age, temperature, charging conditions and repeated discharge cycles.
The difficult part is that a battery can appear normal during everyday operation. When the mains fails and the UPS needs its stored energy, degraded batteries may provide significantly less runtime than expected.
A UPS battery fault can therefore turn a brief power interruption into an unexpected shutdown.
Signs that may indicate battery problems include:
- Reduced runtime
- Battery alarms
- Swollen or damaged battery cases
- Corrosion around terminals
- Abnormal battery readings
- Batteries approaching or exceeding their expected service life
Overloading the UPS
Businesses change, but the UPS does not automatically grow with them.
New servers, network equipment, production systems or other electrical loads may be added over several years. Eventually, the UPS can end up supporting considerably more equipment than originally planned.
Operating too close to capacity leaves less room for further load increases and can increase stress on the system. An overload may also cause the UPS to transfer to bypass or shut down, depending on the severity of the condition and system configuration.
Poor ventilation and excessive heat
Heat is a serious concern for both the UPS and its batteries.
UPS equipment generates heat during normal operation and relies on adequate airflow to control internal temperatures. Blocked ventilation, failed fans, dust accumulation or a poorly ventilated plant room can all increase operating temperatures.
Temperature also has a significant effect on UPS batteries. Persistent exposure to temperatures outside the battery manufacturer’s recommended operating conditions can shorten service life.
Ageing capacitors
Batteries receive plenty of attention, but they are not the only components inside a UPS that age.
Capacitors play an important part in the operation of many UPS systems. Their condition deteriorates over time, with factors such as temperature, electrical stress and operating hours influencing their service life.
If ageing components are ignored, the likelihood of a UPS system fault can increase as the equipment gets older.
Human error
Sometimes the UPS itself is working correctly and the problem comes from an incorrect action.
A bypass switch may be left in the wrong position after maintenance. Equipment can be connected incorrectly. An alarm may be cleared without investigating its cause. Someone may even isolate part of the system without understanding what it supplies.
These mistakes can leave critical equipment exposed.
UPS installation issues
Problems introduced during a UPS install can affect reliability for years.
Incorrect cable sizing, inadequate protection, poor bypass arrangements, unsuitable positioning and insufficient ventilation can all cause problems. The selected UPS also needs to match the load characteristics and resilience requirements of the site.
This becomes particularly important with larger three-phase systems and UPS equipment supporting critical infrastructure.
Missed firmware updates
Modern UPS systems increasingly rely on firmware and networked monitoring equipment.
Manufacturers may release updates to address known issues, improve compatibility or support associated communication and monitoring hardware. If firmware is never reviewed, a site can continue operating with an outdated configuration.
Updates still require care. Applying firmware without checking compatibility, system requirements and manufacturer guidance can create its own problems.
What should you do when you have a UPS fault?
A warning alarm should not be ignored simply because the load is still running.
A faulty UPS may continue supplying equipment while operating with reduced resilience. For example, it could be running on bypass, have deteriorated batteries or have an internal component warning that requires investigation.
Record the alarm or fault code, note any recent events such as a power cut, and arrange for the system to be assessed. Avoid repeatedly clearing alarms without establishing their cause.
The sooner a UPS fault is investigated, the more opportunity there is to address the problem before it affects business operations.
Preventing UPS failure starts before the alarm
Many common UPS failure reasons develop over months or years. Battery degradation, increasing loads, heat and ageing components often provide opportunities for intervention before they cause downtime.
Planned UPS maintenance gives organisations a clearer picture of system condition and helps them make informed decisions about UPS battery replacement, component maintenance and future UPS replacement.
Concerned about a UPS fault or the condition of your existing system? Contact Uninterrupted Power Solutions to arrange a UPS system assessment or discuss a maintenance plan for your site.
