Havent done a job like that, but I am a subcontractor for a pool company.
well I get a job to go change the sand in a filter, and put a new pump on.
Well I do that and the pool company installed a liner and it wasnt ready yet so I couldnt start the equipment see if it leaked, so I left.
Well they started the equipment, it was leaking so I went back, cut off the leaking valve, and made it better by installing 2 valves.
I get a call that afternoon from the customer saying his pumps burnt up, no water is coming through. I said "well sir, it ran just fine a few hours ago. Whats it doing?"
He said, "The trash inside is moving around, and theres no splashing of water and the valves wont open!"
I said, "Sir, thats what its suppose to do. Thats as close to perfect and it can be without jesus himself doing it. And the valves handles should be straight up and down when they are open."
He continued to argue saying, "Well my friend owns a pool company, and he says its burnt up and you installed the valves backward" I kinda chuckled and I told him, "the liner guys will be out to balance the pool later, I'll have them call you when they are on there way"
So they did, and got ahold of the wife, and she said, "The pools flowing fine, but the pumps burnt up" I laughed! They got the wife and the husband at the pump, turned it off, pulled the lid off and water shot out. They said the husbands face went from all hardass to some beat looking dog.
He hasnt called me since.