Pump Not Priming / Losing Prime
Pentair Pool Pump
Severity: CriticalWhat Does This Error Mean?
A pump that will not prime means it cannot pull water from the pool into the pump. There is usually an air leak on the suction side — the pump is sucking air instead of water. Check the pump lid O-ring, valve positions, and water level.
Affected Models
- Pentair IntelliFlo VSF
- Pentair SuperFlo VS
- Pentair WhisperFlo
- Most Pentair pool pumps
Common Causes
- Pump lid O-ring dry, cracked, or not seated
- Low pool water level — skimmer sucking air
- Suction-side valve closed
- Air leak at a pipe fitting or union
- Pump strainer basket clogged blocking flow
- Pump losing prime after sitting idle
How to Fix It
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Check the pool water level.
Water must be at least halfway up the skimmer opening. If water is below the skimmer, the pump sucks air.
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Check and lubricate the pump lid O-ring.
Remove the pump lid. Inspect the O-ring for cracks or debris. Lubricate with a silicone-based pool lube (like Jack's Magic).
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Fill the pump basket with water and quickly close the lid.
Pour water into the pump housing until the basket is full. Close the lid tightly and turn on the pump. This helps it catch prime.
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Check all suction-side valves are open.
Make sure skimmer and main drain valves are open. A closed valve prevents water from reaching the pump.
Frequently Asked Questions
What does priming mean?
Priming is filling the pump with water so it can create suction. A pump cannot move air — it needs water to start the suction cycle.
Can running a pump dry damage it?
Yes. Running dry for more than 30-60 seconds can melt the pump seal and damage the impeller. Always prime before running.