The Chaffoteaux fan assembly is the device that pushes fresh air into the combustion chamber, allowing the gas to be burnt correctly. It also removes the remaining burnt gas after the combustion process is complete. There are safety measures in the boiler to ensure that no gas can reach the main burner if the fan stops working.
Fan assembly
Technical specification
Manufacturer Model No1.018745Brand NameAlphaCompatible WithAlpha C23 and Alpha C27