Bonesy may be right.
http://help.weber.com/warranties/WEBERŪ SUMMITŪ, GENESISŪ AND SPIRITŪ SERIES WARRANTIES
Cookbox.................................10 years, no rust through/burn through (2 years on paint excludes fading or discoloration)
Lid Assembly...........................10 years, no rust through/burn through (2 years on paint excludes fading or discoloration)
Stainless steel burner tubes......10 years, no rust through/burn through
Stainless steel cooking grates......5 years, no rust through/burn through
Stainless steel flavorer bars.........5 years, no rust through/burn through
Porcelain-enameled cast iron cooking grates: 5 years, no rust through/burn through
All remaining parts.....................2 years