Service A
Generac Generator
Severity: MinorWhat Does This Error Mean?
Generac home standby generators show Service A on the Evolution and Nexus controllers when the run-hour counter or calendar timer crosses the first scheduled maintenance interval.
It is a reminder, not a fault — the generator continues to start and run.
Service A typically covers oil, oil filter, and a basic visual inspection.
Once the work is done, the menu has a Reset Service A option that clears the message.
Affected Models
- Generac Guardian 7-22 kW air-cooled
- Generac Guardian 24 kW
- Generac Protector liquid-cooled
- Generac Evolution controller models
- Generac Nexus controller models
Common Causes
- Run-hour counter hit the Service A interval (typically 100-200 hours)
- Calendar timer hit the annual mark since last service
- Counter was never reset after the previous service
- Recent firmware update reset the counter to factory default
- Battery disconnect that restarted the schedule
How to Fix It
-
Read the controller for context.
Press the Enter button on the Evolution controller.
The screen shows current run hours and which Service interval is due.
That tells you exactly what is being asked of you. -
Change the oil and filter.
Turn the generator off at the controller and shut off the gas.
Drain warm oil from the drain valve into a pan.
Spin off the old filter, oil the gasket on the new one, hand-tighten.
Refill with the correct oil weight (typically 5W-30 synthetic) to the dipstick mark. -
Inspect the air filter.
Open the housing and pull the air filter.
Tap clean or replace if heavily clogged.
A 15-20 USD filter is cheap insurance compared to running dirty in dusty conditions. -
Walk around the unit.
Check for rodent damage in the wiring, leaves piled against the louvers, and the battery connections for corrosion.
This is the part Service A really wants you to do — five minutes of walking around catches most problems before they become alarms. -
Run a quick exercise cycle.
From the controller, start a manual exercise cycle.
Listen for unusual sounds.
Watch for smoke from the exhaust beyond the first 30 seconds.
Confirm the battery charger LED is steady on the controller. -
Reset Service A.
On the Evolution controller, navigate to Edit then Reset Maintenance.
Choose Service A.
Confirm.
The reminder clears and the counter starts counting toward the next interval.
Frequently Asked Questions
Will the generator stop working if I ignore Service A?
No.
Service A is informational and does not lock the generator out.
It will start and run during a power outage even with the reminder showing.
But skipping oil changes will eventually cause real engine alarms — Low Oil Pressure, High Engine Temp, and worse.
Can I reset Service A without doing the work?
Technically yes — the controller does not verify that maintenance happened.
But you are setting yourself up for a generator that fails when you actually need it.
The maintenance interval is short and the work is cheap; just do it.