I used to work for a company here that specialised in installing AirCon/HVAC equipment and the majority of our systems worked off of a Pressure switch.
Running a thermostat wire inside the same conduit as the Mains wiring sounds a little dangerous, considering that the T/Stat wire is often very lightly insulated, to say the least.
Speaking of insulation, were these pictures taken before the HVAC guy had a chance to insulate his pipe-work?.
Often the liquid (smaller) line would go un-insulated here.
I was hooking up the power to a new house recently where the Building Inspector refused to sign-off the Building Completion Notice until there was insulation on the Gas (larger) pipe of the AC system.
Un-insulated pipes like this cause water problems from dripping Condensation.