i just moved out to a lakehouse last year. It had a sprinkler system with a centrifugal pump. The pump motor burned up when one leg of the 240v power dropped out (breaker tripped).
I hired a guy who replaced the pump/motor with a National Pump EC-201, 2hp centrifugal pump. While he was at it, he replumbed the supply with new pipes and foot valve.
The foot valve had a metal "cage" like a colander to keep big junk out of the line... unfortunately, the lake has a muddy bottom, and the "cage" got covered with mud and scale to the point that it clogged up. The pump runs on a timer and pump start relay, so I wasn't there to notice it was running dry. The pump will no longer hold a prime or draw sufficient vacuum to supply itself. (The foot valve is working fine, now that I cleaned off its enclosure.)
My question is: what shall I do to re-configure my system to prevent such an occurrance in the future? Is there a low pressure shutoff switch (or something) I can install to prevent the system from running dry in the future? How about a relay that won't power up the pump with less than 220v?