Gloworm - pilot goes out!!!

[Gavsman]

Hi Guys the pilot on my gloworm cobi goes out when I try to use the hot water from the taps or when I turn the heating on - it will let me relight, but if I then try to use the hot water or heating again it just goes out - can anyone help.
Before this started happening there was a sort of loud humming noise coming from the boiler for about a day.

 

[kevplumb]

sounds like a blocked heat exchanger

 

[ChrisR]

" it just goes out "
how quickly?

WHICH BOILER!!!!!!!!!!!!!!!!!!

Is the pump supplied/stuck/turning?

 

[Gavsman]

Hi Guys Thanks for the Help, I have called in an Engineer, was with me for about 10 mins, it was the Flue Fan, it had seized up so he has oiled it for me until next week when I will get a new one fitted.