With summer maintenance season in full swing, Chris Cutler of Riello UPS explores what a preventive maintenance visit should cover and explains how they help data centre operators get the most out of their uninterruptible power supplies.

If the pandemic has taught us anything, it’s that data centres are now as indispensable as utilities like gas, electricity, and telecommunications.

When the world turned to technology throughout lockdown, it was left to the packed racks in data centre server rooms to carry the load, in more ways than one.

Uninterruptible power supplies have played a crucial role too, the unsung hero working quietly behind the scenes to minimise the risk of mission-critical infrastructure going offline.

But a UPS system is a sophisticated piece of machinery in its own right, while wear and tear is unavoidable. So, as we enter the busy summer maintenance period, it’s probably a good time to think about giving your UPS a little bit of TLC to make sure it remains in tip-top condition.

For data centres operators, an ongoing maintenance contract is an invaluable safety net. If the worst happens and there’s a fault with the UPS, a plan sets out the guaranteed emergency response times for engineer callouts.

It also includes provision for at least one planned preventive maintenance visit (PMV) a year. A PMV provides the perfect opportunity to iron out any potential problems before they have chance to develop into something more serious. In addition, a PMV offers the chance to perform system tweaks that optimise performance and efficiency.

Competence is key

Before we explore the ins and outs of a PMV, it’s important you establish that the person you’re entrusting with the job is fully trained and competent. A UPS is a complex piece of kit and it’s not something any electrician or engineer will know the finer working details of.

It’s all too easy for an engineer not completely familiar with the UPS to unwittingly throw an incorrect switch or carry out procedures in the wrong order and you’re suddenly facing a period of unplanned downtime. Never forget that human error is one of the most common – and often avoidable – causes of equipment failure!

That’s why at Riello UPS, we introduced our own Certified UPS Engineer Programme covering both our in-house technicians and personnel from authorised UPS service partners. Successful engineers must complete rigorous training on commissioning, maintaining, and servicing the UPS, and they all have their own unique ID to prove their competence.

So always remember to check whether the engineer is trained for the specific manufacturer and even product line. It’s not uncommon for sub-contractors to be substituted in at the last minute if the original engineer suddenly becomes unavailable.

What should a PMV include?

A PMV will likely start with the service engineer conducting a thorough visual inspection of the UPS to assess whether there are any early warning signs of wear and tear on any of the components. Similar checks should be carried out on the batteries too for any sign of damage, corrosion, swelling, or leaking.

The engineer will also physically check all the electrical connections, paying particular attention to circuit breakers, contactors, fuses, cabling, transformers, PCBs, fans, capacitors, and communications slots.

Many UPS maintenance providers now use state-of-the-art thermal imaging cameras for this task. An increase in heat is a tell-tale sign of a potential failure within both the overall UPS and individual electrical components – it’s a decent guide for when there might be a loose connection.

Of course, the advanced thermal imaging equipment is far more adept at detecting these possible hotspots than the hand or eye of any service engineer, no matter how experienced.

With the batteries, it’s important to check the terminal connections and ensure they are at the correct torque setting.

Your service engineer will then proceed with several mechanical tests on the functionality of the UPS. They’ll download the historical operating and alarm logs, then carry out several tests to see whether the UPS runs properly across a variety of operating modes.

Data centre PMVs often incorporate more advanced functional testing, for example, using load banks to apply dummy loads. Such a simulation enables the engineer to test the UPS and batteries at various load levels without ever interrupting your critical load, which can continuously run using the bypass supply.

In addition to checking the UPS system and batteries, a comprehensive PMV should also assess the installation environment and whether there’s anything in the surrounds that could potentially cause damage. This would include dust, excessive heat or humidity, and poor ventilation.

Ideally, such issues would have been identified – and hopefully eliminated – during the initial UPS installation and configuration. But server rooms aren’t set in stone, particularly in a fast-moving setting such as a data centre, so there’s always the chance that the circumstances have changed since the last maintenance visit.

The PMV also provides the engineer with the perfect opportunity to install any firmware updates. Making sure the UPS is running on the correct and latest software version might sound simple, but it can make a big impact on the unit’s performance and significantly improve energy efficiency, so it’s an important step not to overlook.

Once the engineer has completed all the tests, inspections, and software updates, they’ll fill out a detailed field service report. This document is packed with useful information for any data centre operator or facilities manager.

It contains all the detailed readings from the engineer’s inspections along with a full report of any potential faults and recommended remedial actions, including whether any consumables or components are approaching their end of service life and may need replacing.

Proactive approach pays dividends

The key to good maintenance is to take preventive actions rather than reactive ones. So even though the majority of batteries used in data centre UPS installations come with a five-year or 10-year design life, it’s accepted industry best practice to proactively replace them in year three to four (for five-year design) or year seven to eight (for 10-year design) as it reduces your risk of a serious failure.

A similar approach is advisable with two other key UPS consumables: capacitors and fans. Capacitors work together to store energy and improve power quality, and if even only one or two are reaching their end of service life, it places unnecessary stress on your UPS.

While fans keep the UPS’s inverter, rectifier, and other parts cool enough to operate safely. Failing fans expose these parts to higher operating temperatures, meaning they’ll deteriorate much quicker too.

Your post-PMV report may recommend it’s the time to replace ageing fans and capacitors. This is known as a UPS Overhaul and is a cost-effective way of breathing new life into your system. New capacitors and fans boost the overall performance and efficiency of your UPS, whilst also reducing the risk of a major system failure.

Adopting such a proactive approach extends the lifespan of your UPS, maximising your budget and lowering your total cost of ownership. In addition, it shows shrewd future-planning as it significantly reduces the likelihood you’ll experience a costly period of downtime or need to replace an entire UPS.