Wow.
Well, the easy test is for your dad to now put the pipe back as he had it before, then see if the machine works.
If not, return the pipe to the position the service tech guy put it. Now does it work?
If it works the same in either position, the guy was just making up shit as cover for resetting a counter.
That would be quite a thing.
Mind you, with extreme legislation about appliances these days, maybe the machine detects water loss due to a pipe too low, and refuses to operate? Have you read the stuff about water usage-type restrictions in California recently?
What's the brand?