How to Exercise Your Standby Generator (Weekly Test Run)

Why Weekly Exercise Matters

A standby generator is mechanical insurance. It sits idle 99 percent of the time, and mechanical systems that sit idle develop problems you do not see until the day you actually need them. Weekly exercise runs circulate oil, keep the cooling system wet, verify battery charging, keep fuel lines clear, and give the control system an opportunity to flag faults before an actual outage hits. Without exercise, oil drains off bearings, the fuel in the carburetor (on gas units) varnishes, the battery slowly sulfates, and rubber components dry out. Most generator manufacturers void warranty claims on units that were not exercised according to schedule. Investing 15 minutes of your time to set exercise schedule correctly is the best money you can spend on a $7,000-$15,000 installation.

Generac Evolution Setup via Front Panel

On Evolution controllers (standard on all current Generac Guardian, Protector Home Standby, and Ecogen units), navigate the front-panel menu: Main Menu > Edit > Exercise Time. Use the arrow keys to set day of week (typically avoid Monday morning if you work from home; Saturday afternoon at 2 PM is common), hour in 24-hour format, and minute. Confirm with Enter. You can also choose exercise duration (typically 5 or 12 minutes) and exercise mode (quiet, which runs at 2200 RPM for lower noise, or full-speed at 3600 RPM for a more realistic test). Generac recommends full-speed exercise at least once per month. Confirm the exercise engages by watching the next scheduled time fire.

Generac Mobile Link Setup (Cellular or Wi-Fi)

Mobile Link is Generac's remote monitoring service. It connects your Evolution controller to an app on your phone so you see status, exercise history, and alerts. Setup: buy the Mobile Link module (Wi-Fi or cellular), mount it per the install instructions (wiring connects to the Evolution port), activate service at generac.com/mobilelink. Subscription is free for Wi-Fi, roughly $5/month for cellular (worth it if your generator is out of Wi-Fi range). Once connected, set exercise schedule from the app. The app also pushes any fault notification -- you find out about a low battery or pending service before your next scheduled exercise, not during an outage.

Kohler OnCue Setup

Kohler home standby units (14RESA, 20RESA, 24RCL, 38RCL) use the OnCue controller with OnCue Plus monitoring. Setup is similar to Generac: navigate the front panel to Exercise Time or use the OnCue Plus app. Kohler allows biweekly exercise in addition to weekly on some models, which some homeowners prefer for natural gas units (less fuel used). The OnCue Plus app costs a one-time activation fee, no monthly subscription. Kohler generators can also be exercised remotely from the app if you want to verify operation before a storm.

LP vs Natural Gas Fuel Considerations

Natural gas from the utility flows continuously and is typically unmetered for generator exercise because weekly runs use small amounts (less than 1 therm). LP from a tank is different -- you are paying for every cubic foot burned. A 20kW generator running at exercise idle for 12 minutes per week burns about 0.4 gallons of LP. Over a year, that is about 21 gallons ($60-$90 at typical LP prices). Not a fortune, but budget for it. Also, LP tank level affects output pressure: when the tank drops below 25 percent, supply pressure can drop enough to trigger no-start faults. Keep LP tank above 30 percent during winter exercise season.

When to Schedule Exercise (Avoid Neighbors' Wrath)

A 20kW standby running at 3600 RPM produces 65-72 dB at 7 feet -- about as loud as a vacuum cleaner or a noisy AC compressor. Your neighbors will hear it. DO NOT schedule exercise for 6 AM on a Saturday; people will complain. Good times: weekday afternoons around 2-3 PM when most people are at work, or Saturday mid-morning after coffee. If your HOA has quiet hours, make sure exercise falls outside them. Many Evolution and OnCue controllers default to 2 PM on Saturday, which is sensible. Some HOAs have specific generator exercise rules -- check before setup.

Annual Service Checklist

Weekly exercise is necessary but not sufficient. Annual or 200-hour service should include: oil and filter change with OEM-spec oil, air filter replacement or cleaning (inspect for mouse nests), spark plug replacement (gas units), battery load test, fuel system inspection (leaks, hose condition), cooling fin cleaning (pressure wash or compressed air), enclosure rodent check (mice love standby generators), transfer switch contact inspection (by an electrician, utility off), manometer check of fuel supply pressure under load, and a full exercise run observed by a technician. Factory-certified service typically runs $250-$500 depending on model and region. Many owners do oil and filter themselves and pay for the full-spec inspection every 2-3 years.

Common Exercise-Cycle Problems

Generator fails to run at scheduled time -- check controller battery backup (the RTC needs its own power to track time during utility outages), verify the exercise schedule is saved. Exercise runs but sets a fault at the end -- check the fault code; often low battery voltage as the alternator takes longer than 12 minutes to fully recharge a weak battery, or a sensor wiring intermittent. Generator exercises but shuts down under test load (on units that include a transfer test) -- check fuel supply pressure and oil level. Exercise is too loud -- switch from full-speed mode to quiet mode on Evolution controllers. Schedule drifted after a power outage -- re-enter after any control module reset.

Exercise Keeps the Battery Healthy — Replace It on Schedule

Weekly exercise keeps the battery charged, but the battery itself still wears out in 3-5 years. A fresh Group 26R is the cheapest way to guarantee the generator actually starts when you need it.

Frequently Asked Questions