The boiler a worcester 28CDi is old and not regularly serviced.
# I removed the cover and exposed the fan and noticed when I switched the boiler on and off the small fan blades moved 2 or 3 inches then stopped as though it was trying to go.
I removed the fan assembly-no sign of damage and re-installed.
You could not bother to get your boiler serviced! ( Or are you too mean? )
You then opened the combustion chamber and removed the fan. Thats something you should not have been touching.
Your purchaser could be at risk from your DIY work!
From HSE website
Can I still supply individuals proposing to carry out DIY in their own homes with gas appliances/ fittings?
Yes, providing they are competent to do the work. You may want to remind those wishing to undertake DIY of the possible risks to themselves and to others when they are carrying out gas work.
While Britons are increasingly turning to DIY in an effort to save some money during the recession, one sector commentator has warned that there are some jobs people should never attempt.
Ben Richards, content editor at housetohome, said that tackling plumbing jobs could not only be potentially dangerous, it could also end up costing more than the original job in order to fix any mistakes.
He added that many contractors were licensed to carry out such work safely.
"Only Gas Safe registered engineers should carry out work on gas boilers or appliances and even the most experienced DIYers should stay away from these kinds of jobs," Mr Richards advised.
He went on to recommend that homeowners ensure the professional they hire comes with positive references.
You say this is a DIY site ! ( Actually its DIYnot ! )
The site has an anouncement at the top and partly this says:-
1) If you are found working illegally, (not gas competent), you are breaking the law and the H.S.E. take a dim view. Example HERE
2 ) You will be putting your family at risk of Carbon Monoxide poisoning.
3) Your insurance co is likely to reject any claims being caused by DIY gas work.
This site does not support DIY gas.