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Pool Pump Won’t Start? Here’s Why (+ How To Fix)

If your pool pump doesn’t turn on, your pool will quickly fill with algae, cloudiness, and debris. It’s essential that you quickly find and fix the issue before it causes a bigger problem.

A pool pump that won’t start has one or more of these problems:

  1. Jammed impeller
  2. Malfunctioning motor
  3. Loose wire connections
  4. Clogged pipes
  5. Tripped breaker
  6. Pump timer isn’t set correctly
  7. Faulty pump capacitor
  8. Pump isn’t primed

In this article, I’ll dive into each of these issues to let you know why your swimming pool pump won’t start. I’ll also provide quick DIY solutions and inform you when it’s best to hire a pool technician to handle the repairs.

1. Jammed Impeller

Your pump’s impeller pulls water from the front suction side to push through the top pressure side. The water flow pushes into the filter, removing the debris.

However, a jammed impeller prevents the water from moving. Your pump might not sound like it turns on if the impeller doesn’t move because there might not be enough sound for you to notice.

A jammed impeller needs to be repaired or replaced as quickly as possible. The impeller can trip the breaker, damage the motor, and cause long-term, expensive damage.

The best way to know if the impeller won’t turn is to turn the pump off, open the lid, remove the basket, and see if you can manually move the impeller.

How To Fix

A jammed impeller needs to be replaced if it’s chipped or broken. Follow this method to replace a pool pump’s impeller:

  1. Turn off the pump and the electricity going to the motor at the circuit breaker.
  2. Remove the retaining screws holding the pump’s housing to the motor.
  3. Use a strap wrench and a screwdriver to loosen the impeller, then pull the pump seal out of the back of the impeller (it’s a small, thick ring).
  4. Place the old pump seal in the new impeller or get a new one if you accidentally touch the white portion.
  5. Twist the impeller onto the motor and tighten it with a screwdriver.
  6. Secure the retaining screws to connect the pump housing to the motor.

You can fix a jammed impeller by removing the clog if it’s not broken or rusted. Simply turn off the pump, remove the pump housing from the motor, and pull the debris off of the impeller.

Hair, leaves, and many other things can get tangled with the impeller, so it’s smart to check if you use the pool often or regularly leave the cover off.

2. Malfunctioning Motor

All pool pumps have motors that turn the impeller and pull the water. Without a functional motor, the pump, filter, and all other pool equipment are useless.

Pump motors can get damaged from the following issues:

  • Direct sunlight exposure several hours a day for many years
  • Long-term wear and tear (pool pump motors rarely last longer than five to ten years)
  • Running dry or without a prime
  • Loose wires that overheat the motor from electrical arcing
  • Operating the pump while there’s a dense clog or closed inlet valve

How To Fix

A broken motor needs to be replaced.

Unfortunately, most pool pump motors are soldered or too pricey to make them worth replacing. A lot of the motors cost almost as much as a brand-new pump since they’re the most expensive parts. Therefore, you’re usually better off just buying a brand new pump.

However, you can still try to replace the motor if you want to.

To replace a pump motor, here’s what you need to do:

  1. Turn off the circuit breaker going to the pool pump.
  2. Remove the previously mentioned retaining screws to disconnect the pump housing from the motor.
  3. Use a screwdriver to remove the impeller from the motor.
  4. Remove the wires from the motor and place them away from the pump, so they don’t get wet.
  5. Connect the new motor to the old impeller, then secure the motor to the pump housing with a screwdriver.
  6. Attach the old wires to the new motor in their designated locations.

3. Loose Wire Connections

Loose connections are more than enough to trip a breaker and stop your pump from running.

If you look closely, you’ll see that your pool pump has wires running to the motor and the breaker box.

If the wires on either side are loose, damaged, or disconnected, the breaker will trip, and the motor won’t turn on.

Furthermore, the motor won’t have enough power, even if the breaker doesn’t trip.

How To Fix

Loose connections can occur on the pump’s motor from excessive vibrations, earthquakes, and pests chewing them. Always turn off the circuit breaker before working on the pool pump’s motor or wires.

Each wire should be thoroughly wrapped around its terminal. If they’re not secured, loosen the retaining screw, twist the wire threads to tighten them, and wrap them around the screw before tightening it.

You can tighten the screws on the circuit breaker by turning it off, loosening the retaining screw on the side of the breaker, then pushing the wire further into the breaker. Tighten the retaining screw, and you’ll be good to go.

4. Clogged Pipes

Clogged pipes are one of the few things that can make a pump not turn on that doesn’t directly involve electricity.

If there’s a plumbing clog or a closed valve, the motor will overheat and trip the breaker.

Your pump’s wires, motor, capacitor, and all other electrical components could be fine, but a clogged pipe can prevent the pump from working.

How To Fix

Clogged pipes can be cleared by removing the debris from the skimmer basket, pump basket, unions, and filter. You can use a garden hose with high pressure to blow the lines and clear leftover debris.

If the debris doesn’t come loose, you can try these two suggestions.

  1. Hire a professional pool technician to use a pressurized air hose. These hoses use a lot of pressure to blow clogs loose.
  2. Use a plumbing snake to clear the line. The Breezz Drain Auger fits into your pool pump’s plumbing, and twist it to grab and release excess debris. You can use it with a garden hose to add extra pressure. This 25-foot metal auger is long enough to clear almost any above-ground or in-ground plumbing for your swimming pool.

5. Tripped Breaker

Perhaps the most common reason a pump won’t turn on is that there’s no electricity going to it. And one of the most common things that prevents electricity going to your pump is a tripped breaker.

Breakers can trip for all sorts of reasons, including:

  • Loose electrical connections
  • Faulty breakers, fuses, or GFCI outlets
  • Water in the pump motor
  • Damaged motor windings
  • Overheated motor
  • Water in the circuit breaker box
  • Overloading the breaker with too many amps

How To Fix

I have an in-depth article explaining how to diagnose and fix a pool pump that keeps tripping the breaker. Here’s a brief rundown of some of the solutions:

  • Make sure your pool pump and other equipment don’t exceed the breaker’s maximum amps. If they do, use multiple breakers or upgrade to a breaker with higher amps.
  • Replace the motor if it hums, grinds, screeches, smokes, or overheats. These are all signs that the breaker is tripping due to a malfunctioning motor.
  • Tighten all of the wires. Loose wires will trip the breaker and prevent the pump from turning on.

6. Pump Timer Isn’t Set Correctly

Does it seem like your pool pump won’t come on when you want it to? If so, the timer might not be set correctly.

Some pumps have internal timers, while others use external timers. Older pumps almost always have external timers in the circuit breaker box (though some of them have their own boxes below the breaker setup).

New pumps often use internal programmable timers. You can set them to turn on at a specific time of day and at a designated speed.

These variable speed pumps are quite energy-efficient, but their timers are just as susceptible to electrical issues as the old-school external timers.

How To Fix

Your pump’s timer might not be set, which stops it from running.

If you have an old-school timer, you’ll need to place the markers at your preferred times.

If you need a new external timer, I recommend the Intermatic T104 Electromechanical Timer. It’s easy to use, and it wires directly into the pool pump, allowing you to set start and finish times to whenever you want. Place the markers at the desired times, and you’ll be good to go. Make sure the on/off switch is on at all times.

If you have a programmable timer on a pump (the internal timer), refer to the manufacturer’s guidelines. Every internal timer is different based on the pump’s make and model. Most of them let you cycle between speeds, times, and intervals.

In most cases, you can go to the settings menu, click the timer option, then choose the time of day and which speed you want it to run at.

7. Faulty Pump Capacitor

If your pool pump is not turning on, it might have a damaged capacitor.

The capacitor is a battery that holds and supplies a charge to the motor. Without the capacitor, the motor can’t move the impeller.

A faulty capacitor will prevent the pump from turning on, though it might make a humming noise while it’s wearing down.

How To Fix

The only solution to a faulty capacitor is a new replacement. Here’s how you can do it:

  1. Turn off the circuit breaker.
  2. Unscrew the capacitor housing from the motor.
  3. Remove the wires connecting the capacitor to the motor.
  4. Connect the wires to the new capacitor as recommended by the manufacturer.
  5. Close the capacitor housing and turn on the circuit breaker.

Inyo Pools recommends shorting the capacitor to ensure there’s no residual electricity. You can review their helpful installation video below.

8. Pump Isn’t Primed

A pump that won’t prime prevents the motor from starting. In another article, I’ve covered many reasons a pump won’t prime, including airlocks, electrical issues, and more.

An unprimed pool pump could make many noises before the motor turns off, such as grinding, screeching, humming, and ticking. It’s important to prime the pump as soon as you can to prevent permanent damage.

How To Fix

You can prime the pool pump using this method:

  1. Remove the pump lid and clear all of the debris from the basket.
  2. Fill the pump with water until it overflows, then seal the lid.
  3. Turn on the pump and open the air relief valve on top of the filter to remove excess air bubbles trapped in the system.
  4. Close the air relief valve once the water comes out of it since it means there’s no more air in the lines.

Pool Pump Won’t Start (No Humming Noise)? Here’s What To Do

If your pool pump doesn’t start, hum, or make any noises, something needs to be replaced.

Pool pumps typically make a lot of sounds while they’re dying off. However, extreme water damage or disconnected wires can cause the pump to fail immediately.

So, why doesn’t your pump start or make noises?

  • The motor is shot. If the motor is damaged, it won’t try to start. You’ll have to replace the motor with the step-by-step instructions I provided earlier in the article.
  • The breaker is tripped. A tripped breaker prevents the motor from running, so it can’t make any noises. Fortunately, this issue doesn’t always mean the motor has to be replaced.
  • There’s no electricity going to the motor. Tripped breakers, blown fuses, lack of utilities, and loose wires can limit the power going to the pool pump. If it doesn’t have power, it can’t start or make sounds.

Pool pumps usually make a lot of sounds before they fail. The motor rarely stops running from old age; There’s usually an underlying problem.

In the next section, I’ll discuss a handful of explanations for why your pump won’t start but makes humming sounds.

Pool Pump Won’t Start (But Has Humming Noise)? Here’s What To Do

Is your pool pump not working while it makes strange humming sounds? If so, you’re in the right place.

Pool pumps often hum when they’re pushing water due to the high RPMs, but they have to start to be useful.

Here are a few reasons your pump makes noise and doesn’t push or pull the water:

  • The capacitor is broken. Pool pump motors use capacitors to pull the water. Once the capacitor fails, the motor will hum because it’s trying to pull energy. You’ll have to replace the capacitor if this issue occurs.
  • The impeller is jammed. A jammed impeller prevents the water from flowing. Remove the debris from the impeller or replace it if it’s broken.
  • There’s a closed valve in the plumbing that restricts the water flow. If the valve is closed and the inlet or outlet is blocked, the water can’t go anywhere. The pump will hum and try to pull the water, but nothing happens.
  • The motor froze or the bearings rusted due to cold weather. Pool pumps can’t be exposed to freezing temperatures for too long, or they’ll crack and have motor issues. To prevent these problems, keep the water running at a light trickle during the coldest hours of the day.

Pool Pump Won’t Start After Winter? Here’s What To Do

The winter is a brutal time for pool pumps and other pool equipment. The water can freeze in the pipes and equipment, cracking everything around it.

Furthermore, the frozen water can warp the PVC pipes and render them useless. Small cracks ripple through the plumbing and break the pump’s unions, motor, and impeller.

If your pool pump won’t run after a long, cold winter, the capacitor or motor likely needs to be replaced.

You can test the capacitor with a multimeter to see if it has any electricity. If it doesn’t, the capacitor needs to be replaced; otherwise, the motor needs to be replaced.

The best way to prevent your pump from freezing and breaking during the winter is to run it as often as possible.

Variable speed pumps can run at a very low speed, such as 750 RPMs. This low-speed operation prevents your utility bill from going through the roof. It also doesn’t allow the water to freeze and damage the pump’s motor, impeller, and other equipment.

Pro-tip: You can insulate the plumbing with PVC foam, but don’t paint the pipes black. There’s a common misconception that coating the pipes black will heat the water or protect the pipes. On the contrary, the black paint can overheat the PVC pipes and warp them beyond repair.

Pool Pump Won’t Start On High Speed? Here’s What To Do

Pool pumps that don’t start on a high-speed setting typically have one of these three issues:

  1. The filter is clogged and needs to be cleaned because the PSI is too high.
  2. Your pool pump isn’t designed to go higher than the designated single-speed RPMs.
  3. The higher speed is too demanding of the circuit breaker and pulls too many amps, which trips the breaker.

Other possibilities include a clog in the plumbing that slows the speed and pressure, an airlock that limits the water flow on the pump’s suction side, and an unprimed pump that’s not filled with enough water.

Always open the air relief valve if you think there’s air in the plumbing because it can drastically improve the pump’s performance.

Additional Pool Pump Troubleshooting Resources

If you have any other issues with your pool pump, check out our other pool pump troubleshooting articles: