The Inertaire System (tm) includes all of the pressure regulating controls needed to maintain a positive pressure nitrogen atmosphere in the gas space of the transformer. This nitrogen blanket protects the transformer’s oil from deterioration caused by exposure to moisture or oxygen. When the gas space pressure falls below the low pressure limit, the Inertaire System (tm) automatically feeds fresh nitrogen into the transformer gas space until the pressure is restored to a value above the low pressure limit. When the pressure exceeds the high pressure limit, the system vents the excess pressure to the atmosphere through a relief valve.