Troubleshooting guide
Pool pump not priming
When a pump can't pull water, it's usually sucking air somewhere on the suction side. The fix is often a lid O-ring or a low water level, not a new pump.
Start with the easy, safe checks
- Water level. Pentair's IntelliFlo3 guide says to keep the water about halfway up the skimmer opening. Below that, the skimmer draws air and the pump loses prime.
- Strainer pot full of water. With the pump off and the breaker off, open the lid and fill the strainer pot up to the suction port. Pentair lists "not enough water in strainer pot" as a priming cause.
- Lid and O-ring. Clean the lid O-ring and its seat and make sure it isn't pinched. Jandy's pump manual says debris around the lid seal or a badly seated seal lets air leak in. Hand-tighten the lid only.
- Baskets. Empty the skimmer and pump baskets. A clogged basket starves the pump.
- Valves. Open the suction and return valves for the lines you're using. Pentair's priming steps also open the filter's air relief valve to let trapped air out.
Still sucking air?
Bubbles in the pump basket mean air is getting in. Pentair's troubleshooting chart points to the suction piping and suction valve seals. Jandy suggests checking the suction-side union and its O-ring. A slow hiss or a wet spot near a fitting on the suction side is a good clue.
Variable-speed pumps have priming settings
Many variable-speed pumps run a priming cycle and stop with a priming alarm if they don't detect water in time. Pentair's IntelliFlo3 guide says not to let the pump run more than 30 minutes without priming, and to adjust the priming speed, duration or range if it never primes reliably. Pentair also warns never to run the pump dry, because it damages the shaft seal. See variable-speed pump codes.
What a tech checks next
On a video call a tech will watch the pump basket while it starts, look at the suction plumbing and valves, and check the pump label and settings. From there you'll know if it's an O-ring, a union, a valve, a suction leak or the pump itself.
Common questions
Why won't my pool pump prime?
Usually because it's drawing air: low water in the skimmer, an empty strainer pot, a dirty or pinched lid O-ring, a clogged basket, a closed valve, or a leak on the suction side. Check those first with the pump and breaker off.
How long should a pool pump take to prime?
It depends on the pump and plumbing. Pentair's IntelliFlo3 guide says not to let the pump run longer than 30 minutes without priming. Most pumps prime much faster when the system is airtight.
Can running a pump dry damage it?
Yes. Pentair warns that running the pump dry damages the shaft seal and can cause leaks. Turn it off if it isn't moving water and fix the air leak first.
Related guides
Variable-speed pump codes
Priming, overheat, overcurrent and voltage alarms across the big three brands.
Read the guideFilter pressure high or low
The gauge tells you when to clean the filter, and when something upstream is wrong.
Read the guidePool losing water
Evaporation or a leak? The bucket test tells you in a day.
Read the guidePentair error codes
MasterTemp ERR PS, HLS, IGN, AGS; IntelliFlo3 alarms; IntelliChlor lights.
Read the guideSources
- Pentair, IntelliFlo3 VSF / IntelliPro3 VSF installation and maintenance guide: priming, drive LEDs, troubleshooting chart, alarms and warnings
- Pentair partner support: IntelliFlo VSF pump failure (prime error causes and solutions)
- Jandy (Zodiac), FloPro VS-FHP variable-speed pump installation and operation manual: troubleshooting (copy hosted by Hydropool)
Brand names belong to their owners. Pool Helpline isn't affiliated with or endorsed by any manufacturer. Steps and codes vary by model and year, so always check your own owner's manual.
