by Myles McMorrow, September 26, 2018
The pool pump is one of the most important parts of your pool's plumbing system. It is responsible for creating pressure in your pool, which forces the water to flow through the filter. Think of it as the heart of your swimming pool - without a filter pump, your glistening pool will rapidly become a murky pond of scum.
Unfortunately, there are times your pool pump will not work, and there are many reasons that might occur. In this article, we will cover the most common pool pump problems we hear about at PoolCenter.com.
#1 - The pump doesn't pull water.
If your pump is not moving water, you should first check the skimmer and pump baskets to make sure they are empty and not restricting water flow. Next, make sure your pool filter is clean - a dirty filter can also hinder flow. Once you have checked these, you may want to check the pump impeller. This is the part of the pump that is connected to the motor, and it is responsible for moving the water. Impellers will clog from time to time, especially during spring. To inspect the impeller, open up the pump so you can see inside the impeller housing or volute.
One of the major causes for the loss of pump suction is an air leak in the suction line, which supplies the pump with the water from the pool. You may know this is the issue if your pump will not catch prime, which is when your pump is running at full capacity. A pump is designed to suck water, but it can and will suck air if given the chance. Air has less mass than water, so a pump will suck air before it will suck water. If you think you have an air leak, skip ahead to #5 below.
#2 - The pump is leaking water.
If you see a pump leaking water, it will always be on what we call the pressure side, which is after the impeller. Anything before the impeller is not under positive pressure, but rather negative (suction) pressure, which is called the suction side (see #5 for air leaks).
The causes for a water leak can be a bad impeller housing o-ring, bad shaft seal, bad thread sealant or shrunken threads on the plumbing discharge pipe, or the pipe that comes out of the pump. If it is an o-ring or seal, it is best to get what they call a Go-Kit, which has every seal and o-ring in the pump, in one kit. I always say, if you are going to take the pump apart, you might as well replace all the seals. Pool pump Go-Kits cost about $10-$20, depending on the pump model, and the kits are cheaper than buying all the seals one by one.
#3 - The motor will not work, or it turns off after time.
There are many things that can cause this issue. You want to start by checking for power to the motor. Check your breaker and make sure your timer is set to turn on the pump. If you are getting power, the next thing to check for is sounds. Can you hear the motor hum, or can you hear a click? A humming motor could mean a bad capacitor. Think of the capacitor as a battery (looks like one too) that jumps the motor to start spinning. A capacitor stores up a quick jolt of electricity to start the motor. They can be located in the back of the motor housing or in a hump on the top or side of the unit.
If your motor runs but turns itself off after a time, it may be overheating. Pool pumps use a lot of wattage and need a constant supply. If it is in the middle of a hot day and everyone in your neighborhood has the AC on high, there may be a drop of power causing the motor to overheat. There's not much you can do at that point except maybe run your pump at night when it is cooler. The second leading cause for this is motor fan failure or vent blockage. On the underside of the motor are vents that can get clogged up with dirt and leaves. Make sure you do not have dirt build up and keep them open and clear. Sometimes it's just plain old sunlight causing the motor to overheat; this is common in the southwest and I recommend getting a motor cover to keep the sun at bay.
#4 - The motor/pump is making a loud noise.
Everyone (and their neighbors) hates a loud swimming pool pump. If your pump is loud, the first thing to do is to listen to it. What kind of sound does it make? If it sounds like there are rocks in it, this could be from it vibrating on the pad it sits on - piece of rubber mat underneath might help to stop the noise. If that's not the case, it may be cavitation. Cavitation happens when the pump cannot get enough water fast enough, or the pump is "starved for water." The pump impeller is spinning too fast with not enough water and starts to beat the air molecules out of the water. If you didn't just install an oversized pump, you will want to check the lines for a clog or a closed valve. In some cases it may be a clogged filter or impeller. Clear out any obstructions and you should be fine.
Now, if your pump is screaming (this is what sets off the neighbors) your motor may need new bearings. Bearings are mounted on the pool motor shaft inside the motor to help reduce the friction as the electromagnets make the motor shaft spin. This is a high wear and tear item within the motor. Although the bearings are cheap, the labor is intensive. Most motors have two different sizes of bearings in them, and they usually require a special bearing puller tool to remove them. If you take the motor to a shop, you can get a motor refurbished for about $100. Or, if you are a DIY-er, you can find new bearings HERE.
#5 - The motor/pump is sucking in air.
Pool pumps are supposed to be air tight. With a clear pump lid, you shouldn't see any air in the pump basket. This is rarely the case however, as small air leaks are common. When an air leak gets too large, it can create problems with circulation or keeping the pump primed. The most common causes of a pump air leak include bad thread sealant where the pipe enters the pump, a leaky valve stem on one of the suction valves, or a break in the plumbing. Other sources of air leaking into the system include a loose or old pump lid, a bad pump lid o-ring, or an ill fitting pump drain plug. All air leaks originate before the impeller.
A good test to locate an air leak - and it will sound funny - is to use shaving cream (not gel). Spread the shaving cream over the suction side joints and fittings with the pump on. The pump will try to suck the foam into the pipe because it has less resistance and mass than the water. At the source of the leak, you will start to see the layer of foam dimple as it gets sucked into the system, revealing where the leak is. At this point you will know which part needs to be repaired or replaced.
Another method of locating an air leak is to use the Drain King to pressurize the suction side. Where the water leak occurs under pressure is where the air leak occurs under suction.
So, there you have it - some of the most common reasons for pool pump aggravation. We hope to have helped you through yours!