How To Install a Pool Pump
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Installing a swimming pool pump is not so hard if you have a working understanding of plumbing and electrical systems. The information contained on this page will help you with technical decisions when it comes to pool pumps to help you understand which materials you should use and which you should avoid. Additionally you will learn about minimum clearances for intake pipes, important information about pipe size and how this directly relates to limitations of efficient flow for your system - no matter what your current skill or experience level is with pool pump installations you are likely to learn some important information from this page (and video).
Now, before you run outside and start cutting out your old pool pump you should be aware that the swimming pool industry tends to discourage self-installed equipment like pool pumps. Before you decide to take this installation on for yourself, you should be aware that you may qualify for a shorter warranty period, or no warranty at all in some cases, which is certainly not something you want to learn about after the fact. When you shop from a pool industry professional (contractor, brick and mortar store) you are paying for an experienced technician to evaluate your unique pool installation and provide a suitable pump for your pool...and then install it using industry accepted practices. It might cost a little more than doing the job yourself, but you will very likely have better warranty coverage, and more importantly, the pump should be properly sized for your system. If not, you could have a problem on your hands pretty shortly.
Problems with self-installed pool pumps - It is not a foregone conclusion that a pool owner lacks the technical knowledge to install a pool pump properly. It is more that the average pool owner is not prepared for the technical considerations with choosing and installing a pool filtration pump. If you yourself have a technical designation like plumber, electrician, gas fitter, general contractor etc. then you may also be able to qualify for full warranty on the equipment. It would be best to call the manufacturer for any pool equipment that you are considering to buy and explore this question first before committing to your purchase. Warranty considerations aside, there is also the element of equipment longevity, and more importantly the element of safety. When installed improperly, or when a pump which is too powerful is installed, other equipment (such as your filter) can sustain damage, and you can create suction entrapment hazards within the pool. This situation is more common than you might hope it would actually be.
Pool pump equipment damage and safety - If you install your pool pump wrong, or poorly, or pick the wrong one for your pipe size and other pool equipment, you can easily cause damage (or at least moderate inefficiency) to your pool system. Aside from this inconvenience the primary concern I have with a pool owner installing their own pump is that this can often result in exceeding safety limitations for various parts of the pool. Unfortunately pool owners shop for pool pumps with a "bigger is better" attitude which is seldom an accurate assessment of the situation. More commonly the pool pump was already oversized last time. Or maybe the last two times it was replaced. Now you install a yet more powerful pump and you have a dangerous situation on your hands. Every swimming pool should have no more than six feet per second of suction line water velocity. This is 38 GPM in an 1.5" pipe or about 65 GPM in a 2" PVC pipe. So for clarity, if you have one suction line in your pool only, the skimmer, then your maximum safe flow through your system is only 38 GPM for 1.5" pipes and 65 GPM for 2" pipes. The problem here is that some large pumps want to deliver up to 180 GPM. You can see how these numbers do not line up in the slightest...and this is only scratching the surface. Skimmers themselves are commonly rated to a maximum design flow rate of 55 GPM, rarely up to 75 GPM for some models. Same with main drains. They have a maximum flow rate you are likely to exceed with a larger pump. Plus, a single suction main drain is already a huge safety concern. No pool should EVER have single submerged suction points like a main drain. Yet many pools still have this older, outdated and unsafe design...and then you slap a Ferrari of a pool pump on your system and there you have it. A perfect storm for an entrapment death in your swimming pool. Generally, there is more going on below the surface to a pool than most people realize. Pools are a technical monster and likely there is a lot more to consider than you are giving credence to when you decide to save a few bucks installing your own pool. Okay enough with the doom and gloom stuff, let's talk about how to install pool pumps (better)!
Pipe size for pump installations - The trunk line through your filtration set will be the ultimate factor which affects both your maximum potential flow rate, as well as your maximum potential efficient flow rate. Since the filtration system reduces to a single pipe through the pool equipment the size of this pipe is very important. If you have four suction lines on your pool in 2" pipe, like three skimmers plus a (dual) main drain suction line, you are still limited by the fact that all of these pipes converge to one through the equipment. In a situation like this there is very likely an advantage to increase the size of the single trunk line pipe. You would require multiple suction lines in 2" pipe to feed one 2.5" pipe through the equipment set. Similarly it would take multiple 1.5" suction lines converging at the pump in order to allow for increasing the trunk line size through the equipment set. This really is a pool by pool consideration as there is much to factor in like maximum flow rates for skimmers, main drains and also equipment like your filter, but in the situation where you can do so properly, increasing the pipe size of your trunk line through the equipment set will pay massive dividends in terms of increase maximum flow rates as well as maximum efficient flow rates.
Laminar flow efficiency limitations - In addition to representing the maximum flow velocity in suction lines, six feet per second of water velocity also represents the maximum rate of laminar water flow. Laminar water flow is very efficient. There is very little energy lost in the transmission of the water through the system when it is in laminar flow. Above 6 fps there is an abrupt and sharp increase in inefficiency as the water begins to become turbulent. Friction loss from fast moving, turbulent water is something that ideally you want to avoid with any pool filtration system. At six feet per second the maximum laminar flow in PVC pipe is:
1.5" @ 6fps = 38 GPM
2" @ 6fps = 65 GPM
2.5" @ 6fps = 90 GPM
3" @ 6fps = 138 GPM
4" @ 6fps = 238 GPM
Threaded connections for pool pumps - Many modern pool pumps will come with union connections which do not require any thread sealant or threaded connections at all to the pump. Simply thread on the unions and hand tighten them and you are good to plumb in the pump. For other pool pumps which have female threaded connection points you will require a threaded male adapter to make this connection. Note, the low temperature operating range of PVC fittings makes PVC threaded male adapters less than ideal as heat can cause them to become misshapen and leak over time. Ideally, a CPVC high temperature male adapter is the best way to make a threaded connection to a pool pump. Use PTFE tape, teflon tape it is sometimes called, to wrap the threads a few times before hand tightening into the pump. Once fully hand tight give 1/4 to 1/2 turn further using channel locks or a rounded oil filter wrench. Avoid over-tightening and avoid burying the threads completely into the pump housing. You only need hand tight plus about 1/2 turn more to make reliable threaded connections to a pool pump. Avoid gas tape, the colorful and much thicker teflon tape option. You want the standard plumbers teflon tape...the cheap, white thin stuff. A few wraps of this, between three to five, is all you need to use. Watch the video below for an example of how to wrap the teflon tape the right way and what happens if you wrap it the wrong direction around your male adapter.
Pipe material options for installing pool pumps - While there is a lively discussion online about flex PVC versus rigid PVC for pool installations this all refers to the underground stuff. There is absolutely no doubt that it would be superior (and look better) to install your entire equipment pad in schedule 40 PVC pipe. If you have existing pipes which are poly pipe with barbed pipe connections, be sure to use a double clamp (reversed) to connect a barb x PVC slip adapter and convert to PVC for your pump installation. This will allow you to reliably transition to rigid PVC pipe and make solvent welded connections for the remainder of the installation. A heat gun applied to the poly pipe before you tighten the clamps on the fittings will help a great deal to make sound, water tight connections to these barbed fittings.
PVC Pipe fitting selection for pump installations - Choosing the right fittings for your pump installation will mean the difference between efficient, laminar flowing water versus a pump that does not operate efficiently and can experience early failure relating to heat generated by the pump operation. Schedule 40 PVC is the standard for plumbing fittings for pool equipment installations. Unfortunately DWV (drainage, waste, vent) PVC fittings look very similar to the right fittings which are pressure rated PVC fittings. Local hardware stores rarely carry pressure rated PVC so be sure to check the glue slip joint length for any PVC fittings you are unsure about. DWV fittings are 1/2" to 3/4" in length. Pressure rated PVC fittings have a glue slip length of 1 and 3/8" or more. In addition to these details, you should also be sure to understand the difference between street elbows (slip by spigot), short radius 90's and long radius 90's (sweep elbows). The latter two are both acceptable, where the street elbow is a huge flow restriction and should be avoided on your installation. Sweep ell fittings can be used where you have room to accommodate them, with small improvements to efficiency of flow as a result. Short radius 90's are totally acceptable options to use as well. When the pipe is sized properly using some short radius 90's in the system will not dramatically reduce efficiency of your flow.
* The intake pipe on pool pumps should be a straight run without valves or fittings that is equal to a minimum of 5 times the pipe diameter
Performance curves and flow rates for pool pumps - Choosing the right pump for your pool is the most important part of installing a new pump. There are many brands, makes and models of pumps to choose from and generally these are application specific pumps where you have to match the expected flow rates and resistance to flow to the capabilities of a specific pump. This is more of a technical challenge than many pool owners understand it to be, and one of the main reasons why working with a local pool and spa professional is likely your best option when buying and installing a new pump. For every pump on the market you will be able to look up the performance curve made available by the manufacturer. This will tell you how much water (in GPM) a pump will move for a given resistance to flow. While you might not know the exact resistance to flow of your pool, though in theory it can be measured as TDH (total dynamic head) you can make a reasonable estimate for your resistance to flow to facilitate creating a comparison between pumps. An above ground or very small inground pool might have 20' of head resistance. An average inground pool might have 30' of head. A little bit fancier, more pipes, or equipment located further than 25' from the pool you might have 40' of head resistance. If you have a relatively complex pool system with many pipes, lots of peripheral equipment, a rooftop solar heater etc. then you might have 60' or more of head. Using these estimates you can now look up the actual flow rate that each pump would deliver under these estimates for resistance to flow. This gives a very apples to apples baseline for comparison. To see examples of many of the most popular pool pumps flow rates at 30' and 60' of head resistance check out the chart near the bottom of this page on variable speed pool pump reviews.
PVC primer and solvent cement - When installing pressure rated PVC fittings you need to use a primer, and then a solvent cement to chemically weld the fitting to the pipe. Ignore advice you see online or hear from your neighbor about how they never use primer and their fittings are always "fine". They are not and primer is required as part of solvent welding PVC. As for primer color, do yourself a favor and use clear primer for equipment installations and save the purple primer for in the trenches where it won't matter so much if you accidentally knock over the can. As for solvent cement (PVC glue) you can use any number of colors, which all represent specific PVC solvent cement formulations. Gray is standard and always good to use. Blue is pool and spa specific, which is also fine. Again, something like a "705 clear" solvent cement from weld-on would be a great choice. The clear is just as strong, but more forgiving should you spill some on the equipment pad. Note, one of the most important things you want to do when installing a new pool pump is to cover it completely with rags or towels to protect it from drops of primer and solvent cement which can get splashed around when you are gluing the pipes and fittings together. There is nothing worse than a brand new pool pump with a hazy, stained strainer lid because you spilled glue or primer on it! If you have CPVC unions or pipe to connect to be aware that any PVC solvent cement is suitable for this. Only if you need to preserve the heat rating of the CPVC at the connection point to the PVC pipe do you need the CPVC solvent cement. Generally, this is something not needed at the residential grade, and is usually used for commercial installations where there is a specific call for all heat rated pipe and connections. In that case CPVC solvent cement would be required. For residential pools the CPVC union (or valve) is enough to protect from the heat of the appliance it is connected to. The point where PVC connects to the PVC is generally far enough from the heat that there is no concern for the solvent welded joint.
Aside from the technical tips on this page, the way you actually install a pool pump is generally to place all of the equipment exactly where you want it positioned, and then to begin on the suction side of the pump. Start with the suction manifold and plumb this into the suction side of the pump. From there you plumb to the filter next, then out from the filter to the heater, salt chlorinator or whatever peripheral equipment you have down the line from the pump and filter. Also, don't be afraid to dig up the suction and return lines where the meet the equipment pad to re-route them underground or to space each pipe further apart. When you stub up pipes for an equipment pad try to leave 8" to 12" of space in between each pipe so as to allow room to build the suction and return manifolds cleanly.
Perhaps it would also be a good idea to read this article about why did my pool pump die early? to make sure you do not have any of the potential problems with your pump installation which might lead to early failure. You can also take a look at this page with pool equipment installation tips which also covers more of the materials and processes that you should use, as well as a 50 video series of reviews of actual pool equipment installations to help you learn more about what not to do when installing a pool pump.
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Swimming Pool Steve is an award winning, second generation swimming pool specialist from Ontario Canada and one of the most trusted voices in the swimming pool industry. With over 20,000,000 views on the Swimming Pool Steve YouTube Channel, winner of the Pleatco Pool & Spa Industry Leadership award and author of hundreds of pool and spa articles both online and in print. Steve is committed to helping pool and spa owners as well as pool and spa industry workers learn more about the technical side of building, renovating, repairing and maintaining all types of swimming pools and spas. Follow Swimming Pool Steve on Facebook, Twitter and YouTube.
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