When the solenoid is excited, the piston is driven for {HEAD ~ movement} to switch {TAIL ~ a flow path} within the housing 
to switch
When the solenoid is excited , the piston is driven for { HEAD ~ movement } to switch { TAIL ~ a flow path } within the housing
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH