5 Causes of Intermittent Pump Prime Loss

Suction-side air leak A small air leak on the suction side lets in just enough air to break prime intermittently. The pump primes fine but loses prime off and on.

Pump lid O-ring A dry, cracked, or unseated O-ring is the most common cause. Lubricate it with silicone and ensure it’s clean and snug.

Skimmer basket weir stuck open A stuck weir flap can cause intermittent prime loss as the water surface bounces. Check and free the flap.

Low water level in pool If the water level drops below the skimmer, the pump sucks air. Maintain proper water level.

Hairline crack or buried pipe leak If all else fails, you likely have a crack in the suction pipe or a buried leak. This requires a professional.