This site has a lot of info.
First Alert, protecting what matters most Our CO combo detector was going off , I called the BRK/First Alert service dept and they sent me two new ones. They have a warranty of I think 5 yrs.
As of July 1, 2008 all new construction (including residential) in Florida with fossil fuel heat, appliances, fireplaces or attached garages will be required to have a carbon monoxide alarm installed within 10 feet of sleeping areas.