Time and our experience has proven that vertical installations on the top centerline prove to be most reliable over the long term. The top centerline usually places the thermocouple nozzle in the external thermal management system (weather shield) vent along the top centerline of the vessel. This is ideal since the thermocouple and mounting nozzle temperature is kept closer to that of the vessel shell design temperature, minimizing corrosion. If the top works of the thermocouple interfere with a vent roof, it is perfectly acceptable to make a provision for the thermocouple terminal housing to extend through it. The top centerline location simplifies the physical installation.