Question
What is most effective way to use electrical/mechanical controls to prevent a pump start relay controlled pump from startup if the pump has lost prime?

Answer
Hi Joe

This may help you. Find it at: http://store.waterpumpsupply.com/lowprescutga.html

The Gard-it switch is wired in series with a conventional pressure switch. If pump loses it's prime the system pressure will fall considerably below the cut-in point of the regular pressure switch. Gard-it will disconnect the pump motor. The system is placed in automatic operation by depressing the manual reset lever until the system pressure exceeds the Gard-it cut-off level



Specifications
昐tandard setting: 12 PSI cut-off
昍ange: 3 to 20 PSI
旴ottom connection: 1/4 FNPT (Female pipe thread)
昅ain spring adjustment:
昑urn clockwise to increase cut-off pressure.
昑urn counter-clockwise to decrease.
旵apacity:
?-1/2 HP @ 120 Volts
? HP @ 230 volts single phase
? HP @ 230 volts three phase
? HP @ 230 volts three phase
?/4 HP @ 120 volts DC
?/4 HP @ 32 volts DC
旾nstallation For Lost Of Prime Protection:
昅ount Gard-it Switch to the pump discharge line.
旵onnect the "load" terminals on the Gard-it Switch to the "line" terminals on the pump pressure switch.
旵onnect incoming power lines to the "line" terminals on the Gard-it Switch
旽old down the manual lever on the Gard-it switch until the pump is primed and the system pressure exceeds 12 PSI.