Hi , thank you very much for your reoly to my post.
To answer your questions:
I have no idea how is connected to the wiring as i moved to the house and it was there.
Yed i know what pcb look like and fuse too. I have some good knowledge about that .
I dont have the manual unfortunatel, but i looked online for it and found one .However and funny enogh it did nit show any useful info or image related to the fuse ir even wiring.
Other posts suggested that fuse might be located inside the chimney . Removing the chimney dies nit sound easy by the look of it .
Kind regards
Jack, March 2018