{HEAD ~ A safety device} for avoiding {TAIL ~ entrapment} at a water reservoir drain by using a vacuum operated switch to interrupt power to the reservoir pump and by using a pressure pump to generate a positive pressure to dislodge the obstruction from the drain should a blockage occur 
for avoiding
{ HEAD ~ A safety device } for avoiding { TAIL ~ entrapment } at a water reservoir drain by using a vacuum operated switch to interrupt power to the reservoir pump and by using a pressure pump to generate a positive pressure to dislodge the obstruction from the drain should a blockage occur
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH