John Faulkner
Member
Every time I turn the pump off it won’t start back up without me adding water to the basket first is that normal or does it mean I have a leak somewhere.
Pump keeps losing prime after shutting off
- Thread starter John Faulkner
- Start date
Hanry Carter
Member
I’ve had this too it’s usually a suction-side air leak. Check the lid O-ring, silicone-lube or replace if flat/cracked, then snug the fittings and drain plugs. After that my pump held prime.
Isabella Morales
New member
Also check the fittings on the suction side a tiny crack or loose joint can pull in air. After I tightened everything and added a little silicone lube to the O-ring, my pump stopped needing to be primed every time.
Ronald Taylor
New member
Also check the fittings on the suction side; a tiny crack or loose joint can pull in air. After I tightened everything and added a little silicone lube to the O-ring, my pump stopped needing to be primed every time.
Benjamin Tate
Member
That’s not normal, and it almost always means the system can’t hold water once gravity takes over.
Since it runs fine while it’s on, the leak is usually small and on the suction side. When the pump shuts off, that tiny air path lets water drain back toward the pool and leaves the basket empty. Lid O-ring is the most common, but one spot people forget is the pump drain plugs. Those can seep air without ever dripping water, especially if the gasket is flattened or the threads aren’t sealed well.
Another thing to think about is whether the pump sits above the waterline. If it does, even a perfect-looking system can lose prime if there’s no functioning check valve or if an existing one isn’t sealing fully. The pump doesn’t have much help from gravity in that setup, so it only takes a small leak to break the siphon.
A simple test is to fill the pump basket completely, tighten the lid, then shut the pump off and leave it overnight. Before you touch anything in the morning, pop the lid and see how much water is still there. If it dropped significantly, you know it’s draining back somewhere and not just struggling to self-prime.
Start with lid O-ring and drain plugs, then move upstream to unions and valves. Once a pump can hold water while it’s off, it usually primes instantly without any fuss.
Since it runs fine while it’s on, the leak is usually small and on the suction side. When the pump shuts off, that tiny air path lets water drain back toward the pool and leaves the basket empty. Lid O-ring is the most common, but one spot people forget is the pump drain plugs. Those can seep air without ever dripping water, especially if the gasket is flattened or the threads aren’t sealed well.
Another thing to think about is whether the pump sits above the waterline. If it does, even a perfect-looking system can lose prime if there’s no functioning check valve or if an existing one isn’t sealing fully. The pump doesn’t have much help from gravity in that setup, so it only takes a small leak to break the siphon.
A simple test is to fill the pump basket completely, tighten the lid, then shut the pump off and leave it overnight. Before you touch anything in the morning, pop the lid and see how much water is still there. If it dropped significantly, you know it’s draining back somewhere and not just struggling to self-prime.
Start with lid O-ring and drain plugs, then move upstream to unions and valves. Once a pump can hold water while it’s off, it usually primes instantly without any fuss.
Ibrahim Mwangi
New member
Looking at the replies, what Manikshaw and Harry Carter mentioned points to the same issue. A pump that needs refilling every time usually can’t hold prime because air is sneaking in on the suction side. In my case it was just a tired lid seal. Once that was fixed and snug, the pump restarted normally without manual priming.