A thermal station has five valves that control the delivery of steam to the outside  The use of these valves must comply with the following operations First, if you open the No  1 valve, you must also open the No  2 valve and close the No  5  Second, if you open the No  2 valve or the No  5 valve, you have to close the No  4 valve  Third, do not close the No  3 and No
4 valves at the same time
Valves No.3 and Valves No.5