Manual Shutdown Procedure for Liquid-Cooled Generac Generators

Liquid-cooled units are the larger systems — bigger homes and commercial buildings — and they shut down differently from the air-cooled units beside a typical house.

This is for planned situations: a scheduled service visit, a fuel delivery, or maintenance work somewhere in the building. It is not an emergency procedure.

Shutting it down

1. Open the cabinet

Use the key or the latches to reach the front control panel.

2. Set the controller to OFF

On an Evolution or Nexus controller:

• Use the arrow keys to navigate to OFF
• Press Enter to confirm

The generator runs a cool-down cycle of roughly 60 seconds, then stops. The display should read Generator is Off.

Let it finish. The cool-down is doing real work.

3. Turn off the generator’s main breaker

Find the main breaker inside the generator — usually a large black switch — and flip it to OFF.

This disconnects the generator from the building’s electrical panel. It is what makes the work safe: it prevents accidental backfeed, which is the hazard that matters most to anyone working downstream.

4. Optional — the automatic transfer switch

Only do this if you have been told to, or for extended maintenance.

• The ATS is usually mounted near your main electrical panel or the utility meter
• Set it to Utility, OFF, or Manual depending on the model

This stops the generator starting automatically if utility power drops while work is in progress.

Putting it back in service

1. Turn the main breaker back ON

The large black switch inside the generator.

2. Set the controller to AUTO

The display should read Switched to AUTO — Ready to Run.

If you switched the ATS in step 4, return it to its normal position as well. Confirm both before you leave. A liquid-cooled system left in OFF or with the ATS in Manual will not run in the next outage, and nobody finds out until the lights go off.

Call us if

• The generator will not shut down, or will not restart
• Any warning or fault code appears
• There are visible leaks, a fuel smell, or signs of overheating
• It makes an unfamiliar noise while running

On liquid-cooled equipment these are not things to work through yourself. The units are larger, the fuel systems are bigger, and the consequences of a wrong guess scale with them.