Consider adding an additional alarm lamp and buzzer to trigger the chamber in the event of a temperature spike from either a heater or LN2 issue. In the early days when the chamber was running for 8 continuous hours, especially during the night shift when there is no technician available, a few incidents occurred (example: LN2 Magnetron Valve malfunction). Even with the chamber halted (Eurotherm cut off system), the LN2 was still purging due to the faulty mechanism. This created icing across the internal chamber of the unit. It is for this reason that the unit needed to be scrapped and production cost took a hit, which is not productive. By implementing this system, the blower will be powered by additional circuitry SSR creating air flow and avoiding the potential for icing and replacements in the future.
Tip provided by: Abdul Halim Abdul Rahim, Honeywell Aerospace Avionics Malaysia