Boilers can come with a warranty that covers the boiler vessel and all components that were packaged along with the boiler when it was originally shipped from the factory. However, the length of the warranty can vary depending on the manufacturer and the type of boiler.
Certain parts of the boiler may be under a longer warranty than others. For instance, the heat exchanger may be under warranty after the second year and every year after that, while all other parts of the boiler may only be warranted for a year after they were installed. A boiler installer may warrant labor and installation of the boiler for the first year.