A transportation refrigeration system includes a transportation refrigeration unit, a gas circuit connected to the transportation refrigeration unit and arranged to connect thereto a split bottle gas supply having a plurality of electric lock-off valves, and a controller. The controller is operably connected to the transportation refrigeration unit and is responsive to instructions recorded on a memory to close the electric lock-off valves of the split bottle gas supply. The instructions also cause to the controller to receive a first measurement of gas pressure in the gas circuit, open a first of the electric lock-off valves of the split bottle gas supply, receive a second measurement of gas pressure in the gas circuit, and determine health of the first electric lock-off valve using the first and second measurements of gas pressure in the gas circuit. Related methods and computer program products are also described.