Here are a couple shots of the unit
Are those wires in the center connected to the pressure switch? I would guess that is it, or at least some kind of switch (2 wires)
That clear air line looks like a vacum line to me, but I don't know. Either way, if I pull that while it is running, I can produce the same error code. (?)
Also, after the unit shuts itself down with the error code, I can unplug it then replug it in, and it will run great (until it fails again which seems to be "random")
The hoses going outside the house seem fine.
The water heater ones are the two on the right
The inlet is on the far right with the valve