The fan is reasonably easy to change, but as stated before on other questions, this is a potentially dangerous boiler if not sealed and tested correctly after putting the case back on (due to the nature of being a positive fan), is liable to push fumes into the area/room around the boiler.
Pay up front and get a RGI to do the job, for your own safety. If you don't have the correct methods for post testing, don't start the job.
There have been fatalities from fumes from these boilers. You have been warned!
Carefree, September 2010
