if you feel competent, remove the boiler front cover by lifting, use pozidrive screwdriver to remove 4 screws on combustion chamber cover. Remove fan connections (note which connections they go on) and remove 3 screws and plastic tubes (note which goes where). Gently pull fan out. Putting the new fan in is the reverse. Be careful not to break the little plastic fan blades.
xyzbird
December 2008