16-Year-Old Irrigation Pump Loses Prime After Hour: Suction Line Leak

16-yr pump, winterized yearly. Worked 3 weeks, then lost prime. Replaced all suction connections. Primes, builds pressure, runs ~1 hour, then loses prime. Restart brings prime back, but opening any valve draws air. 2 HP, creek source, 1.5" suction reduced to 1.25", 75' run, 15' lift.

Filter/Suction Line Issue

Matt: "Is it possible the screen/filter is getting partially plugged and causing the problem? That would be my first guess. Creeks tend to have different particles to filter at different times of the year."

Pressurize to Find Leak

"Try hooking a hose to the pump and pressurize the whole system. Then carefully check the suction line. The complete pipe, not just the fittings. As I'm sure you know, any leak even a tiny one will affect the pump. Your problem is definitely the suction side of the pump. It's just the process of finding the leak."

Pressurizing the suction line (with pump off) makes air leaks blow bubbles/soapy water, revealing the spot. Creek debris cycles explain the 3-week delay.