Why Did My Pool Pump Fail?
This article is intended to help you explore the potential reasons that you experienced, at least what you feel to be, an early pool pump failure. So this begs this initial question of "how long should a pool pump last?" and the correct answer to this will depend on a lot of factors. For example, do you run your pool pump 24/7/365? Probably not, as most pool owners only run their pump for part of the day, and further to this most swimming pools are not even open 12 months per year.
Also worth noting, a pool pump running in a moderate climate area like Seattle for example will experience nowhere near the same level of heat (a major contributor to electric motor failure) as a pool pump located somewhere in Arizona. So in order to get an accurate answer about how long you can expect a pool pump motor to last will depend greatly on where you live, how many months per year your pool is in operation, and what kind of environmental conditions the pump must endure.
How long should a pool pump last? An average pool pump should last for about 60 months of operation, say manufacturers.
This relative range of 60 months gives you a ballpark number to work with to help you to understand how long you should expect a pool pump to last before it is expected that things might start to wear out, break, or require service. So if you live in Florida and run your pump every day of the year, then you could expect that your pump might run for around five years or so before you might need some service or repairs. However if you live in Canada where the pool is closed for six months every year, then you could hope that your pump would last for around 10 pool seasons before you might need a new one. It is important to understand that these are general guidelines (directly from the pump manufacturers) as to how long they expect their products to last in the field. Some people will get more, and some people will get less, and this is considered a normal variance.
So what if you understand all of this information described above about average service life expectancy for pool pumps...but yours definitely died early? Is there a chance that there is something wrong with the pump itself, or how it was installed, that caused it to die earlier than it should have? Absolutely! When I worked for one of the largest pool equipment manufacturers in the world I was in charge of technical support for pool pumps for the entire Country. If you called the 1-800 number on the side of your pump because it was not working, it was my phone that would ring. During this time I learned a lot about what can make a pump fail early.
Early Pool Motor Failure
There are a lot of things that can make a motor fail, and in the vast majority of cases it is usually not one, individual thing, but more a series of compounding factors that all add up to create an environment that is not congruent with sustained electric motor life. If you have had a pool pump fail on you then it is highly likely that one, or a few, of these factors are to blame.
Pump Defects - While it is possible that there may be a problem with the installation, it is also entirely possible that the pump had some sort of defect that allowed the failure to happen. These things do happen, although rarely when compared on the national average, but that still means thousands of field failures of pumps installed all over North America every year. A reality of the world that we live in today is that it is a "throw away culture" and long ago the focus shifted away from quality in manufacturing and instead now price is the ultimate pursuit. Pool pumps built today are done so cheaply, and often with inferior quality components, versus pumps from the 60's, 70's and 80's. Sometimes you can still find an ancient bronze pump humming away a full 50 years into its service life. 50 years from now I highly doubt any pool pumps being installed this year will still be running. I once knew about a series of pumps that were made in China and assembled locally where a full 50% of the impellers disintegrated upon initial startup of the pump. A failure rate of 5% is a mitigated disaster for a product line. 50% failure rate out of the box is a testament to how cutting material and product costs can go one step too far very easily. Defective pumps, and entire defective pump lines do exist out there.
Pump Ran Dry / Overheated - Assuming that there was no pre-existing problem with the pump, if the pump was allowed to run dry even a single time, or ran with the strainer basket jammed full of leaves, then it could have overheated and the main seal could have distorted slightly. The pump would still likely start up and operate normally, but water would begin to drip out of the bottom center - or more that it would, were it not being drawn into the electric motor. Chlorinated water being drawn into an air cooled electric motor is a guaranteed failure for the bearings, which results in increased mechanical friction, heat damage, melted windings, increased amperage draw, and ultimately too much heat being lost in reduced efficiency. It could be that the pump had a long term leak that easily went unnoticed until the bearings in the motor became corroded. When the main seal starts to leak (bottom, dead center) it is not usually a stream of water. It is usually only a drip. The floor might even soak up the drips as fast as they fall such that you never see a damp spot or wetness. Still, the location of this leak allows for this water to be drawn into the electric motor. Traditional single speed pool pumps use the movement of ambient air through them to keep cool. If chlorinated water is drawn in along with this air, you can count on experiencing an early pump failure. This, specifically, is one of the reasons why the new generation of variable speed pumps are superior to their previous successors, since almost all new VS pumps are a TEFC style motor (totally enclosed, fan cooled) which means they are vastly less susceptible to environmental contaminants like dust, moisture, and chlorinated water getting into the motor.
Chlorine Storage Near Pump - Since we are talking about the damage that chemicals like chlorine can do to electric motors, is your pump located inside a closed room like a shed? Is the chlorine for your pool (liquid or buckets) stored in the same room? If they are, this is almost 100% sure to be the problem that killed the pump. Keep chemicals completely on their own. You might think that just because you have a lid on your chlorine products that they should not cause any problems for your pump, but you would be wrong. Chlorine gas, even in small amounts, can and will greatly accelerate corrosion on metal surfaces nearby. I know of a few pool companies that have lost thousands of dollars in tools and equipment for storing these items too close to their chlorine storage tanks or chlorine displays. Better to be safe than sorry and get a sealed container or storage bin where you can safely and securely store your pool chemicals away from all of your pool equipment.
Resistance To Flow - As a pool filter gets dirtier and dirtier, it will get harder and harder for the pump to push the water through the system. What is the pressure that your system operates at? How often are the filter cartridges cleaned (or sand filter backwashed / DE filter stripped and cleaned)? Anything that you can do to reduce flow restrictions will help your situation, but more day-to-day try to be proactive to keep your system pressures as low as they can be. A common error is for cartridge filter owners to use an acid solution to clean the filters when a degreaser is actually needed first. Using an acid wash first effectively cooks the oils permanently into the filter paper. Some pool chemicals can cause similar restrictions to flow in cartridge filters, like flocculant. It is also possible to restrict flow with valve orientation, but more commonly, with poor selection of plumbing fittings when the system is initially installed. In many cases, no definitive answer will present itself as to why a pool pump failed early, but in my experience these same pool systems tend to be the ones plumbed in with the worst flow restrictions. The worst offenders in this regard are easily poor layout, and street elbows instead of long elbows or sweep elbows. Each fitting adds to the energy lost in moving the water through the pipes. Fast moving water causes more friction, and more turbulence in the water, which add to the efficiency losses. The vast majority of plumbing flow restrictions all happen on the equipment pad so consider replumbing with a larger diameter pipe to reduce the velocity of the water, as well as reduce system pressures. Replace excessive fittings and short sweep / street elbows with long sweep elbow fittings. Do NOT have a tight radius elbow fitting directly into the suction side of the pump, and if possible avoid the same on the discharge side. You should have 10x the pipe diameter in a straight run leading into the pump suction for optimal flow and minimal water turbulence, and the pressure side pipe should have a sweep elbow fitting instead of a tight radius elbow.
Lack Of Pump Bonding - One of the most common deficiencies that pool equipment installations share is a lack of bonding to the equipment. The confusion comes from "grounding" and "bonding" being somewhat similar, such that the average technician (and electrician) usually can not explain the difference. This results in many installers mistakenly believing that the ground wire that is along with the hot and neutral wire is all a pump needs. In reality, the pump also needs an equipotential bonding wire connected to the casing of the appliance. In the 50 part video series I made inspecting pool equipment installations this turned out to be the most common deficiency across the board: Pool Equipment Installation Review Series. Every metal component in, and around, a swimming pool needs to be bonded. This forces the electrical potential of the metal to be equal to the other metals within the system. Without a bonding wire, the casing of the pump (or any metal) could have a slightly different potential voltage than other metal components, and according to electrical theory, this results in a current transfer between the two metals. How does this happen? The water itself is the conductor between these different pieces of metal. Pure water itself actually does not conduct electricity, but impurities within the water, such as salt, do conduct electricity. Failure to bond the casing of a pump, or any other equipment that contains metal, can result in that equipment becoming the anode in a galvanic couple. This causes an accelerated rate of damage to metal components from corrosion, so if your pump was not bonded it is possible that internal metal components have aged prematurely. Salt water pools will experience more dramatic damage from corrosion, however this still happens in any swimming pool that is treated with chlorine, or has a TDS level above a theoretical zero.
Electrical Supply Problems - If you are electrically inclined I might also check voltage supply. Especially if the pump is wired for 120v and especially if the circuit is a long distance run, you could have an appreciable voltage drop. Motors specifically would be prone to failure if running outside of spec voltage all the time. For example your pump is probably rated for 108 to 128 volts or something similar. Disconnect it from the pump electrically (isolate the circuit) and test the voltage to verify that you have the line voltage that you expect to see. A long run, overheated conductors, damaged conductors (like from mice chewing them), undersized conductors and loose connections can all cause a voltage drop. If you are experiencing equipment failure earlier than you should be then checking your electrical system would be a good idea. Unfortunately diagnosing electrical problems can also be elusive to figure out. Sometimes the voltage of an isolated circuit will test to be fine, but when you reconnect the equipment and put the circuit under load, a problem presents itself. Conductors (wires) heat up when under load, and when hot, can increase resistance to infinity (approaching open circuit). Checking the voltage of a loaded circuit is a good idea, as is using an amp probe to monitor the amperage draw of the circuit. Failing conductors will continue to draw more current under the same load and RPM settings the longer the pump is running, where this number should remain relatively stable in an electrical circuit without deficiencies.
Lack Of Airflow / Overheating - Pool equipment is made to be installed outdoors. There are some places however that it just gets too hot to have your pump sitting out in the sun. That is why products like these pool pump covers exist. In the areas where the sun will kill your pump you need to take steps to protect it. So does that meant that pumps are fine outside in the sun everywhere but Australia and Arizona? No - of course not. It is always a good idea to protect your pump from not just sun...but also heat in general. One of the ways that a pump can overheat is actually from being located in a closed room, or shed, even if there are open air vents in the room. On a very hot and sunny day with no wind, how much fresh air do you think blows into this room? It could easily be that the pump overheated and some of the windings shorted together and from that day forward every time there was a really hot, not windy day, the pump got a little worse and started to pull more and more current. Having an open vent to fresh air is known as being a passive ventilation system...but it is entirely possible that the heat from the running pump motor combined with no wind and summer sun can overheat the entire room that the pump is located in. To resolve this as a potential concern you could install an active ventilation system on a contactor such that a vent fan turns on any time the pump is running. Heat kills electric motors and anytime a motor fails early you should consider that heat probably was one, if not the singular, cause for the problem.
Plumbing Leaks - Don't you hate it when you go to take a drink out of a straw, but there is a hole somewhere in the straw and all you can manage to get is a mouthful of air and frothy beverage? Well...how "burnt out" would you be if your job was to drink out of straws all day every day, but the straw always has a hole in it? As I am sure you can imagine, this creates a not-ideal situation when you apply this simple example to your swimming pool system. A pool pump is made to be self priming, and can evacuate air from the plumbing system by passing it through all the way back to the pool returns. But if your pump is constantly pulling air then it will need to work harder, and experience more turbulence in the water, than a pump installed on a fully closed system. Also, the priming cycle is the hardest part for pool pumps. If you add water to your pump and start it up it should catch prime almost right away. If your pump needs to fight gravity, and plumbing leaks, and it takes a few minutes to catch prime every time you start your pump, then I would expect this pump to wear out much sooner than a pump installed on a leak free, or better yet, a flooded system where the pump is located below the water level in the pool.
Every step that you can take to improve the operating conditions that your pump runs in will increase the chances that you will get the maximum life possible from your pump. If you found this information helpful you might also like to read this article that talks more generally about the different components of your pool, and how to go about getting the longest possible life from each of these parts:
Why did my pool heater fail early?
How to get the most life from your pool
Proper pool heater installation checklist
How much power does a pool pump use?
How long do variable speed pool pumps last?
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