Best things to reduce stress on an ac unit is to have clean air filters, clean coils and proper refrigerant charge. No need to close vents off, that's just silly talk right there.
The switch he replaced or touched, did it have a red button on top located inside the burner compartment? There is only 2 switches that would cause a hard lockout and can't be reset with a power cycle.
I've been recovering from neck surgery from June and had great success with using CBD oil and CBD infused pain cream. Just beware a lot of companies use fillers. The brand I use is organic hemp seed with CBD-rich whole hemp extract nothing more and it's 3rd party tested for purity. They even offer a 30 day money back guarantee.
If the return water temperature is below 130* longer 10 to 15 minutes you'll have condensation. I personally wouldn't worry about thermal shock, that water would have to be pretty cold to cause that. The Hydro control is doing it's job to maintain water temperature.