A low water sensor within {TAIL ~ the vessel} is connected to {HEAD ~ a relay coil} with contacts interrupting the flow of electrical energy to the heating element when water is beneath the level of the sensor 
A low water sensor within { TAIL ~ the vessel } is connected to { HEAD ~ a relay coil } with contacts interrupting the flow of electrical energy to the heating element when water is beneath the level of the sensor
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH