Generator vs. ATS Maintenance: Why You Need Both Serviced (and Why Most Providers Only Do One)

Backup power failures happen for a lot of reasons, and while generator failures are among the most common causes, a failed automatic transfer switch accounts for plenty of them too. Here’s how the sequence actually works: when utility power goes out, your ATS is the first system to respond. It senses the loss of power and sends the start signal to your generator. Once the generator reaches proper voltage and speed, the ATS transfers the load over to emergency power. Those events happen within seconds of each other, and your facility is counting on both systems to execute without fault.

Understanding the difference between ATS maintenance and generator maintenance isn’t just a technical distinction. It’s the difference between a backup power system that performs when you need it and one that fails at the worst possible moment.

What Generator Maintenance Actually Covers

Generator maintenance focuses on the mechanical and electrical components of the generator set itself. A standard preventative maintenance visit covers engine oil and filter replacement, fuel filter service, coolant checks, battery condition, and load bank testing can be performed alongside a generator maintenance. For most standby units running fewer than 50 hours per year, a full PM2 inspection once annually meets manufacturer standards, though a semi-annual check is advisable to catch developing issues between service intervals.

Batteries degrade without regular inspection, coolant breaks down, and fuel quality deteriorates in storage. All of these are issues a disciplined maintenance schedule catches before they become failures. What generator maintenance does not cover, however, is what happens upstream of the generator. The controls, the transfer logic, and the switching mechanism that connects your generator to your building’s electrical system are all part of the ATS, and that equipment requires its own service program.

LionHeart services both your generator and your ATS under one program so nothing falls through the gaps.

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What ATS Maintenance Covers (and Why It’s Different)

An automatic transfer switch for generator systems acts as the brain of your backup power setup. When utility power drops, the ATS detects the outage, signals the generator to start, monitors incoming power quality, and executes the physical transfer of the load. A failed or degraded ATS can prevent a fully functional generator from ever delivering power to your facility. Because the switch operates automatically, there is no manual override standing between a malfunctioning ATS and a total loss of backup power.

LionHeart’s automatic transfer switch maintenance involves inspecting and exercising the transfer mechanism, testing voltage and frequency sensing, verifying time-delay settings, cleaning contact surfaces, checking for loose connections, and confirming that the switch will operate correctly under both normal and emergency transfer scenarios. The contacts inside a transfer switch carry significant current loads and degrade over time, especially in facilities that experience frequent utility fluctuations. Catching that wear before it causes a failed transfer is exactly the kind of thing proper ATS maintenance intervals are designed to do. These tasks require different tools, different testing procedures, and a different knowledge base than standard generator service, which is exactly why many providers only offer one or the other.

The Risk of Servicing Only One

A generator can pass every maintenance checkpoint and still fail to power your building if the automatic transfer switch for generator operation has a corroded contact, a misconfigured time-delay, or a sensing relay that has drifted out of calibration. The generator did its job. The system still failed.

ATS maintenance gaps are also harder to detect because transfer switches sit idle for long periods and show no visible symptoms until they are called to operate. There is no oil to check, no coolant to sample, no filter to inspect. The only way to confirm the switch will perform is to test it, and that testing needs to be done on a schedule, not reactively. By the time a problem surfaces, it is during an actual outage: exactly when you need the system most.

For facilities in regulated industries like healthcare, data centers, or critical infrastructure, this is not only an operational risk. NFPA 110 generator requirements mandate that transfer equipment be tested and maintained as part of a complete Emergency Power Supply System (EPSS) inspection program. Treating the ATS as an afterthought is not just a reliability gap. It is a compliance exposure that can result in failed inspections, citations, or worse.

Why Most Providers Only Do One

It comes down to specialization. Some providers focus on generator sets and have deep engine knowledge but treat the ATS as outside their scope. Others handle electrical switchgear but don’t service the generator itself. Facilities that piece together service agreements from multiple providers often end up with a gap right at the integration point between the two systems, which is precisely where most failures occur. When something does go wrong, it helps to have an expert onsite who can understand both the generator and the transfer switch.

A single-provider program eliminates that ambiguity entirely. LionHeart’s technicians are EGSA certified and trained across both generator systems and transfer switch equipment. The same team that handles ongoing commercial generator maintenance also evaluates the ATS and the full system interface, because backup power reliability depends on how those components work together, not just how each one performs in isolation.

Why LionHeart Is the Right Call for Both

A fully maintained backup power system includes regular ATS maintenance, annual generator service with load bank testing, semi-annual inspections, and documented service records that satisfy both OEM requirements and applicable codes. LionHeart’s technicians are EGSA certified and trained across the full scope of backup power equipment, not just the generator and not just the switch.

LionHeart’s skills-based dispatch means the right technician is matched to every job, with your unit history and site logistics already on file so there is no re-learning the system at each visit. There is no coordination overhead, no gaps between service scopes, and no finger-pointing when a problem comes up. Whether your facility runs a single standby unit or a paralleled generator configuration, every component in the power transfer path gets the attention it needs under one service relationship. See how LionHeart delivers that coverage for facilities and businesses across the Midwest.

Generator vs. ATS Maintenance: Why You Need Both Serviced (and Why Most Providers Only Do One)

What Generator Maintenance Actually Covers

What ATS Maintenance Covers (and Why It’s Different)

The Risk of Servicing Only One

Why Most Providers Only Do One

Why LionHeart Is the Right Call for Both

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