This is more plumbing and electrical but ...
One of my techs call with a problem that went like this.
(1 year of schooling, 2 years in the field, according to him he knows everything)
Tech: I am over here doing the PM and they are telling me the water heater isn't working.
Me: Okay, what is the problem they are having?
Tech: They have no hot water.
Me: And what have you done?
Tech: I checked for alarms and I am not getting any. I checked the pilot light. It is on. I checked to make sure it is heating the water it is. I checked the pump and it is working. I think there is leak somewhere and the water isn't making it to the bathrooms.
Me: is the water heater constantly heating?
Me: Is there a big puddle of steaming water in the building somewhere?
Me: Then it is not a leak. Are you sure you checked the water pump correctly? You are positive it is flowing water.
Me: Okay I will be there in an hour. Until then keep working on the PM.
Needless to say, he didn't like the conversation we had 30 minutes after I got there.