Troubleshooting guide
Pool pump humming but not starting
A hum with no spin means the motor is getting power but can't turn. Hayward's pump manual names a jammed impeller as the first cause. Don't leave it humming: turn it off while you check.
Turn it off first
What's usually wrong
The motor is trying to start, but something is stopping the shaft from turning, or the motor isn't getting what it needs to get going. Hayward's MaxFlo VS manual lists "Motor hums, but does NOT start" with one cause: the impeller is jammed with debris. Leaves, pine needles, hair pins and small toys that get past the basket can wedge in the impeller. Other causes, like a failing motor part or a wiring or voltage problem, need a tech to check.
Two safe first checks
- Look in the pump basket. With the pump off and the breaker off, take off the strainer lid and basket and look inside the pump for debris. Jandy's FloPro manual gives these same steps for a blocked impeller: power off, remove the lid and basket, remove any debris you can see, then put the basket and lid back. Hand-tighten the lid and make sure the O-ring is seated.
- Look at the breaker and any timer or controller. Don't keep resetting a breaker that trips again. Hayward lists tripped breakers, blown fuses and open switches or relays as reasons a motor won't start, and those are for an electrician to check. On a variable-speed pump, note any message on the screen; see variable-speed pump codes.
If it still hums after the basket is clear, stop there. Getting to the impeller means taking the pump apart, and Hayward says to have a qualified repair professional open the pump and remove the debris.
Get a tech on video
On a video call a tech can listen to the pump, look at the motor and drive labels, and tell you whether it's a jammed impeller, a motor part, or an electrical problem for an electrician. You'll know what part, if any, you need before you buy anything.
Common questions
Why is my pool pump humming but not running?
The motor has power but the shaft can't turn. Hayward's pump manual names a jammed impeller as the cause. Turn the pump and breaker off, check the strainer basket for debris, and have a tech open the pump if it still hums.
Is it bad to leave a humming pool pump on?
Yes, turn it off. A motor that's stuck and humming is not moving water and can overheat. Leave it off until you've found the cause.
Can I fix a humming pool pump myself?
You can safely clear debris from the strainer basket with the power off. Opening the pump to reach the impeller, and anything inside the motor or drive, is a job for a qualified pool tech.
Related guides
Pump not priming
Pump runs but the basket won't fill. Almost always air or water level.
Read the guideVariable-speed pump codes
Priming, overheat, overcurrent and voltage alarms across the big three brands.
Read the guideElectrical safety & pool lights
Tingling, flickering lights or a GFCI that won't reset. Treat it as an emergency.
Read the guideFilter pressure high or low
The gauge tells you when to clean the filter, and when something upstream is wrong.
Read the guideSources
- Hayward, MaxFlo VS variable speed pump (IS2303VSP2) owner's manual, section 11 Troubleshooting: motor will not start, motor hums but does not start
- Jandy (Zodiac), FloPro VS-FHP variable-speed pump installation and operation manual: troubleshooting (copy hosted by Hydropool)
- Pentair, IntelliFlo3 VSF / IntelliPro3 VSF installation and maintenance guide: priming, drive LEDs, troubleshooting chart, alarms and warnings
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.