A UPS system is a complicated piece of kit in its own right. That’s the case whether you’re talking about a small plug and play device backing up a home gaming setup or a vast multi megawatt installation protecting vital server rooms and electrical equipment.
Just like any other electronic device, how well you look after and maintain it can have a major impact on its performance, reliability, efficiency, and eventual lifespan.
Later in this piece, we’ll take a look at a couple of the key components that make up a UPS but are amongst the most prone to failure.
But we’ll kick-off by highlighting the importance of ongoing maintenance and explaining what a typical service visit should cover.
TLC for your UPS
New UPS systems are obviously covered by warranties if anything goes wrong. Indeed, much of the Riello UPS range comes with a 5 year extended warranty as standard. But a warranty only offers a ‘best endeavour’ response, it’s not a guarantee of a speedy solution if there’s an issue.
Many mission-critical sites such as data centres, factories, or hospitals opt for the safety net of an ongoing maintenance plan spelling out guaranteed Emergency Response Times for engineers to attend site if something goes wrong.
Such agreements include at least one planned preventive maintenance visit (PMV) a year. But even with a UPS that isn’t covered by a contract, regular service visits are highly recommended.
Think of a PMV as you would an annual ‘health check’ for your car or boiler, offering reassurance that everything’s working as it should. It also gives you the chance to identify and fix any potential problems before they can spiral into something more serious.
ABCs of a PMV
Before describing what a PMV will typically cover, it’s important we just cover the issue of competence. It’s vital you know that the engineer working on your UPS is fully trained.
General maintenance or electrical engineers are unlikely to have sufficient product-specific knowledge, so always ask for proof the engineer is trained for your manufacturer and model.
Remember, sub-contractors can often get substituted in at the last minute when the original engineer becomes unavailable!
A PMV typically kicks-off with a visual and physical inspection for signs of wear and tear, as well as checking batteries for swelling, corrosion, or leakage. The engineer will also check, and if necessary, tighten all electrical connections, such as the capacitors, fans, PCBs, and breakers.
Engineers then proceed to mechanical and functional tests, where they’ll download historical alarm and performance logs, before carrying out several tests to see how the UPS runs in various operating modes.
Next up is installing firmware updates, as having the latest software has a positive impact on the UPS’s overall performance and efficiency.
Finally, the service engineer will complete the maintenance register and produce a detailed service report providing a full rundown of any faults and recommended remedial actions i.e. any components that are due for replacement.
Capacitor care
Now we’ve explored the ins and outs of a service visit on your UPS, let’s consider a couple of the key components that play an integral part in your unit.
A typical UPS contains dozens of capacitors ranging in size from a mini drinks can to a tube of Pringles. These various capacitors (AC input, AC output, DC) work together to enhance overall power quality by smoothing, filtering, and storing energy.
Capacitors age over time as the electrolyte, paper, and aluminium foil inside all degrade physically and chemically. All these factors all impact on performance. As a rule of thumb, capacitor lifespan shortens due to combination of overuse, excess current, and excess heat, which evaporates the solution inside the capacitor and builds up the pressure.
You get a pretty good idea of when a capacitor might be about to fail – you’ll spot deformations caused by excess heat, there might be a fluid leak or scorched wires, or the valve cap might protrude, a tell-tale sign of stress.
If just a single capacitor fails, the rest of the set has to pick up the slack, which in turn places them under greater stress. This downgrades your UPS’s ability to filter power and it also increases the likelihood of experiencing harmonics.
In favourable operating conditions, a UPS capacitor can have a service life of up to 10 years. But industry best practice recommends swapping capacitors out between years 4-8. This is replacement is often carried out at the same time as swapping out the UPS’s fans, which help keep key components such as the rectifier cool.
Such a swap out is often referred to as a UPS overhaul and it can help lengthen the lifespan of your unit, as well as improving its operating efficiency.
UPS battery basics
The overwhelming majority of UPS failures are linked to problems with the battery set – the account for around 80 per cent of all issues.
Single-phase and smaller UPSs are typically installed with five year design life batteries, while larger three-phase UPS batteries will come with a 10 year design life.
Assuming perfect operating conditions, you’d imagine those batteries should last for five or ten years respectively, wouldn’t you? But of course, there’s no such thing as a ‘perfect’ environment!
There are so many factors that can impact the lifespan of your UPS batteries, including the frequency and depth of discharge, or the operating voltage. But by far the biggest cause of premature battery failure is high ambient temperature. Most UPS batteries have a rated capacity based on operating temperatures of 20-25oC. For every 10oC increase, service life halves.
Guidelines from respected industry body EUROBAT (Association of European Automotive and Industrial Battery Manufacturers) stipulate UPS batteries reach the end of service life when capacity falls below 80 per cent of the original.
So for batteries with a 5 year design life, it is best practice to proactively replace them in service year three or four. For 10 year design life batteries it is year seven or eight. This provides a safe margin to mitigate any drop in performance.