Do not use solenoid valve, pressure switch,  
    flow switch, on foot switch in the environment where the large electric current or the strong magnetism exist.  
  As for solenoid valve, check in the instruction  
    manual whether the lubrication is needed. If needed, use turbine oil first class
ISO VG32 on the equivalent.
 
  In the case of double solenoid valve, do not  
    energize both solenoids.  
  Avoid the load over the switch's allowable  
    maximum load.