Technical Pitfalls after Genset Commissioning: How Small Changes Impact Reliability

A genset that passes commissioning checks all the boxes. It starts cleanly, runs at full load and meets performance expectations. At that point, it’s tempting to think installation is complete.

In reality, installation is only validated at that moment in time. Issues can surface later when a space is reconfigured, parts are added or operating parameters evolve. Many of these modifications seem minor. They don’t feel like they should affect how a genset operates. But every system is interconnected, and when conditions around a genset change, it can erode reliable power.

After decades supporting installation and commissioning, I’ve seen some missteps lead to reduced performance, higher costs and even genset failure. Today, I would like to share three common post-commissioning changes, which are easy to ignore. Here’s what can go wrong – and how to reduce your risk.

Gensets rely on consistent airflow for cooling and combustion. Ventilation designs account for heat rejection, air paths and clearances. Commissioning verifies that everything works correctly – but only under the specific conditions present at that time.

Problems start when those conditions change. Let me share two real-world examples:

• A genset at a data center in Malaysia successfully passed commissioning and ran normally during early operation. One day, the customer called the Cat^® dealer that the genset’s voltage and frequency dropped after running at full load for one hour. An onsite inspection found that the inlet air temperature had increased by roughly 20 °C, triggering a derate. The issue wasn’t the genset – a wall had been added to the engine room less than one meter from the radiator, restricting airflow and trapping heat.
• In a Chinese manufacturing factory, two gensets sharing the same space were commissioned to operate individually. Years later, when the customer decided to start running them in parallel, one struggled to reach full power because it was pulling in hot exhaust air from the other unit. Nothing mechanical had changed, just the airflow environment.

Ventilation issues like these rarely cause immediate failure. More often, they show up as reduced output or derate that limits how much power the genset can deliver. I often remind customers: the worst time to learn about a system’s weak spot is when you’re counting on it most. It’s one thing to diagnose an issue after the fact, but nobody wants to be in the position where you’re only discovering what went wrong because everything has already come to a stop. That’s a lesson most of us have felt firsthand – and it’s never a good feeling.

All gensets produce vibration when they run. Installation designs keep it within acceptable limits – but those limits can change if equipment is added later.

Case in point: A genset powering an Indonesia data center passed commissioning with no issues and ran reliably during early operation. Later, the customer rerouted power cables to create more space inside the enclosure, mounting a large bracket directly to the genset to support the cables. After about 100-hour operation, the generator experienced significant bearing damage. Why? The added structure changed how vibration traveled through the system, pushing it outside its original design limits.

This type of issue is easy to be missed because the genset may continue running normally for some time before problems appear. Vibration-related issues often surface as accelerated wear or fatigue damage long before outright failure.

The main components of an exhaust system include, but are not limited to, the exhaust manifold, turbocharger, wastegate, piping and silencer. Bellows is one type of the flexible connections, which is used to isolate the weight of the exhaust pipe from the engine, to relieve exhaust components of excessive vibrational fatigue stresses and to allow relative shifting of exhaust components.  The bellows allow for limited offset of the exhaust components, but over offset would cause the failures of the bellows.

Here’s an example: A genset exhaust system was routed through the engine room roof. The installation team noticed a small misalignment between the manifold and exhaust piping and added bellows to accommodate movement – but didn’t check the alignment specification. The genset ran for nearly a year before the turbocharger failed. Technicians found damage caused by debris from a cracked bellow. It had been under constant stress, eventually failing and releasing fragments that were carried downstream by the exhaust flow into the turbocharger.

Exhaust-related issues often follow this pattern, showing up as exhaust leaks, heat damage to nearby components or emissions levels drifting out of spec. By the time a major component fails, the system’s been under stress for months.

The key is recognizing when an installation assumption no longer holds true and a change – planned or unplanned – affects the system as a whole.

• Ventilation: Reassess airflow any time you reconfigure the engine room or change how gensets operate together. Even small layout adjustments can alter air inlet and outlet paths, affecting cooling and combustion air.
• Vibration: Treat added structures – brackets, cable supports, breaker panels – as system changes, not simple add-ons. Always recheck vibration, since additional mass can alter behavior over time.
• Exhaust: Verify alignment and weight limits whenever exhaust systems are installed or modified, especially when routing through building structures or using third-party components.