Your standby generator is your last line of defense when the power goes out. But a generator that has not been properly maintained is a generator that may not start when you need it most. Just like your HVAC system or your car, a standby generator requires regular seasonal maintenance to stay reliable. Here is a complete seasonal checklist that every Aiken homeowner should follow to keep their generator ready year-round.
Why Generator Maintenance Matters
Standby generators sit idle most of the time. They run weekly self-test cycles for a few minutes, but they may go months or even years between actual power outages that require extended operation. This long idle time creates specific maintenance challenges that do not apply to equipment that runs daily.
Oil breaks down over time even when the engine is not running. Batteries lose charge and degrade. Fuel system components can corrode or clog. Coolant loses its protective properties. Rodents and insects find their way into enclosures and chew on wiring. Without regular maintenance, any of these issues can prevent your generator from starting during the next outage.
The statistics are sobering. Industry data shows that the number one cause of generator failure during outages is a dead or weak battery. The second most common cause is fuel system problems. Both are entirely preventable with routine maintenance. A generator that receives annual professional service has a start reliability rate above 99 percent. A neglected generator drops below 90 percent within just a few years.
Spring Maintenance Checklist
Spring is the most important maintenance season for generators in the Aiken area. You are coming out of winter, which may have included ice storms and cold snaps that stressed the system, and heading into the severe thunderstorm and hurricane season that runs from May through November. Spring is the time to ensure everything is ready for the heavy-demand months ahead.
Oil and Filter Change
Change the engine oil and oil filter every spring regardless of how many hours the generator has run. Oil degrades over time from condensation, heat cycles, and chemical breakdown. Most residential generators use 5W-30 or 10W-30 synthetic oil. Check your owner's manual for the correct type and quantity. A typical 22kW Generac requires about 2 quarts of oil.
When changing the oil, inspect the old oil for metal flakes or a milky appearance. Metal flakes indicate internal engine wear. Milky oil suggests coolant contamination, which is a serious issue requiring professional diagnosis.
Air Filter Replacement
Replace the air filter every spring. In the Aiken area, pollen, dust, and red clay particles clog air filters faster than in many other regions. A clogged air filter restricts airflow to the engine, reducing power output and increasing fuel consumption. In severe cases it can cause the engine to overheat and shut down under load.
Spark Plug Inspection
Remove and inspect the spark plugs. Look for carbon buildup, electrode erosion, and correct gap spacing. Replace spark plugs every two years or if they show signs of wear. Fouled or worn spark plugs cause hard starting, rough running, and reduced power output. Most residential generators use standard automotive-style spark plugs that cost a few dollars each.
Battery Testing
Test the starting battery with a load tester, not just a voltmeter. A battery can show 12.6 volts at rest but fail to deliver enough cranking amps to start the engine. Load testing reveals the battery's true condition. Replace any battery that fails the load test or is more than three years old. Generator batteries typically last three to five years in the Aiken climate.
Clean the battery terminals and cable connections. Apply a thin layer of dielectric grease or battery terminal protectant to prevent corrosion. Check that the battery charger is working correctly by measuring the charging voltage, which should be between 13.5 and 14.5 volts when the charger is active.
Coolant System Check
For liquid-cooled generators (typically 20kW and larger), check the coolant level and condition. The coolant should be at the proper level and free of contamination. Test the coolant's freeze protection and pH level using test strips. Replace the coolant every two to three years or per the manufacturer's schedule.
Inspect coolant hoses for cracks, swelling, or soft spots. Squeeze each hose to check for deterioration. Replace any hose that shows signs of aging. A burst coolant hose during an outage will shut down your generator within minutes.
Summer Maintenance Checklist
Summer is peak storm season in Aiken. Thunderstorms, tropical systems, and the occasional hurricane bring the highest risk of extended power outages. Your generator needs to be in top condition from June through September.
Weekly Exercise Verification
Confirm that the generator's weekly self-test cycle is running properly. Listen for it during the scheduled time each week. The generator should start within a few seconds, run smoothly for 12 to 20 minutes, and shut down automatically. If you notice it not running on schedule, investigate immediately. Common causes include a failed battery, a tripped breaker on the battery charger circuit, or a control board fault.
Enclosure and Ventilation
Inspect the generator enclosure for wasp nests, ant colonies, spider webs, and rodent activity. In the South Carolina summer, insects and small animals are drawn to the warmth and shelter of the generator cabinet. Clear any obstructions from the cooling air intake and exhaust openings. Blocked ventilation causes overheating, which triggers automatic shutdown under load.
Fuel System Inspection
For propane generators, visually inspect the fuel lines from the tank to the generator for damage, corrosion, or leaks. Check that the manual shutoff valve operates smoothly. For natural gas generators, ensure the gas meter and supply line connections are secure and free of corrosion.
If you have a propane tank, check the fuel level. A 500-gallon tank powering a 22kW generator will be consumed in approximately five to seven days of continuous operation. Top off the tank before hurricane season to ensure you have maximum runtime available.
Transfer Switch Inspection
Visually inspect the automatic transfer switch for signs of overheating, loose connections, or corrosion. Check that all contact points are clean and tight. The transfer switch is the most critical component in the system because it handles the actual power switching between utility and generator. A transfer switch failure means no power even if the generator is running perfectly.
Fall Maintenance Checklist
Fall is your final opportunity to address any issues before winter storms arrive. The transition from hot to cool weather also creates specific maintenance needs.
Full Load Test
Simulate a power outage by having a qualified technician test the generator under actual load. This means disconnecting utility power at the transfer switch and running the house on the generator for 30 minutes to an hour. This test verifies that the generator can handle your home's actual electrical demand, not just run unloaded during the weekly exercise cycle.
A load test reveals problems that weekly exercise cycles cannot detect. The generator may start fine with no load but stumble, surge, or overheat when it has to power your air conditioner, water heater, and kitchen appliances simultaneously. Catching these problems in the fall gives you time to address them before winter.
Belts and Hoses
Inspect all belts for cracks, glazing, and proper tension. A loose or worn belt can cause the alternator to underperform or the cooling system to fail. Check all hoses for deterioration, and replace any that show cracking, softness, or bulging.
Exhaust System
Inspect the exhaust system for leaks, rust, or damage. Exhaust leaks near the generator enclosure can allow carbon monoxide to accumulate, creating a safety hazard. Ensure the exhaust outlet is directed away from windows, doors, and air intakes per the manufacturer's specifications.
Control Panel and Monitoring
Check the generator's control panel for any fault codes or warning indicators. Clear any resolved codes and investigate any active alarms. If your generator has remote monitoring (Generac Mobile Link, Kohler OnCue), verify that it is communicating properly and that your account notifications are set up to alert you to problems.
Winter Maintenance Checklist
Winter in Aiken is generally mild compared to northern states, but ice storms are a real threat. The December 2014 and January 2018 ice storms caused widespread, multi-day outages across Aiken County. Your generator must be ready for these events.
Battery Condition
Cold weather reduces battery capacity. A battery that performed adequately in the summer may not have enough cranking power to start the engine in 25-degree weather. If you did not replace the battery in the spring and it is more than two years old, consider replacing it proactively before the winter storm season.
Block Heater Operation
Most standby generators include an engine block heater that keeps the engine warm for faster starting in cold weather. Verify that the block heater is plugged in and functioning. You can check this by feeling the generator enclosure on a cold morning. If the block heater is working, the enclosure will be noticeably warm to the touch compared to ambient temperature.
Freeze Protection
For liquid-cooled generators, verify that the coolant has adequate freeze protection. In Aiken, protection to 0 degrees Fahrenheit is sufficient for typical winter conditions. Test with a coolant hydrometer or refractometer. If the freeze protection is inadequate, drain and replace the coolant with the correct mixture.
Snow and Ice Clearance Plan
While heavy snow is rare in Aiken, ice accumulation on the generator enclosure can block ventilation openings. After any ice storm, check the generator before it needs to operate and clear ice from the intake and exhaust openings. Never use a heat source to melt ice on or near the generator because of the fuel connections.
Common Failures from Neglected Maintenance
Homeowners who skip maintenance often do not realize their generator has a problem until the power goes out and nothing happens. Here are the most common failure modes that result directly from skipped maintenance:
Dead Battery
This is the single most common cause of generator failure. The battery slowly loses its ability to hold a charge over time. The weekly exercise cycle keeps it partially charged, but a weakened battery may not have enough reserve to crank the engine in cold weather or after a period without exercise. Annual battery testing and replacement every three to four years prevents this failure completely.
Fuel System Blockage
Fuel system components can accumulate deposits, especially in propane generators where regulator diaphragms can stiffen and fuel orifices can clog. Regular fuel system inspection and cleaning prevents these blockages. In natural gas systems, the solenoid valve can fail from corrosion if not exercised regularly under load.
Low Oil Shutdown
Generators have a low-oil-pressure safety shutdown to protect the engine. If the oil level drops below the minimum or the oil degrades to the point where it cannot maintain proper pressure, the generator will shut down and refuse to restart. Regular oil changes and level checks prevent this entirely.
Coolant Failure
Old coolant loses its corrosion inhibitors, leading to internal corrosion in the engine and radiator. This corrosion can cause leaks, blockages, and overheating. In severe cases, corroded coolant passages can lead to head gasket failure, which is an expensive repair. Replacing coolant on schedule costs a fraction of engine repair.
Rodent Damage
Mice and rats are attracted to the warmth of generator enclosures. They chew on wiring, insulation, and fuel lines. A single chewed wire can prevent the generator from starting or cause it to shut down during operation. Regular enclosure inspections catch rodent activity before it causes wiring damage.
The Value of a Professional Maintenance Plan
While handy homeowners can perform some maintenance tasks themselves, a professional maintenance plan ensures nothing gets overlooked. At Unity Power & Light, our generator maintenance service includes everything on this checklist plus advanced diagnostics that require specialized tools and training.
Our technicians perform load bank testing, transfer switch exercise and inspection, fuel pressure verification, exhaust emissions analysis, and control board diagnostics that go beyond what a homeowner can do with basic tools. We also document every maintenance visit, creating a service history that supports your manufacturer warranty and adds value if you ever sell your home.
A maintained generator lasts 25 to 30 years. A neglected generator may fail within 5 to 10 years. The annual cost of maintenance is a small investment compared to the cost of generator replacement or the consequences of being without power during an extended outage.
Contact Unity Power & Light at (803) 220-4491 to schedule generator maintenance or to set up an annual maintenance plan. We service all major brands including Generac, Kohler, Briggs & Stratton, and Champion throughout Aiken County.