Jul 26, 2014 - 02:41 PM
h(Manual Recirculation): Press to alternate between recirculating air inside the vehicle or pulling in outside air. When selected, the touch screen button lights up to indicate that air is being recirculated. This helps to quickly cool the air inside the vehicle or prevent outside air and odors from entering. Pressing this button cancels automatic recirculation. Press AUTO or AUTOhto return to automatic operation; recirculation runs automatically as needed. Manual recirculation mode is not available when in Defrost or Defog modes.
The button referred to the second under the "Auto" button on the right of the climate display.
Manual, (with pictures) free: http://www.chevrolet.com/content/dam/...
Source: Volt Owners Manual