This happened a lot of years ago, in another country. A friend of mine was doing plumbing work into the house of a 60 years old widow, when she spoke about a ghost in her house. The lady complained about hearing thumping noises without any visible cause, and compared them to the sounds made by a children playing with a ball. The plumber heard that, instructed the lady to sit still and do not worry, started the heating, went to the place where the sounds were starting from and opened up the valves in the heaters venting a lot of air from the pipes.

The sounds stopped immediately and the plumber tried to explain to the old lady that the air in the pipes was causing the noises, but she did not want to hear about that. According to her, the plumber was a good man and banished the "ghost" with his good character.

End of the story, apart for the plumber receiving a lot of calls from local people asking for an exorcist/ghostbuster! This affected his reputation in an interesting way.