When purchasing a new in-ground swimming pool, you need to determine what size pool pump is required. There is a tendency to purchase a bigger pump than what is necessary because people think bigger is better. However, not only does this lead to higher operating costs, but you may also be overpowering your filter system. As a general rule, you should have a pump that filters all the water in a pool in an eight-hour period. This page will show you how to select a pump that filters all the water in your pool in eight hours.
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carlos805 Posted: 9/7/2013
I have a pool 12'x34', shallow end 3.5', deep end 8.5'. I have a heyward DE4800, old school. after calculating everything here, I think my pool holds about 18400 gallons of water. my DE4800 is shot and I need to replace it. a neighbor is giving me a Sta-Rite system 2 PLM150 filter system. will this work. the pump I have now is 3/4 HP.Reply
InyoPools Product Specialist Dennis R. Posted: 9/3/2013
Frog - $70 a year seems very low for a VS pump savings. See our guide on "How to Save Money Using a Variable Speed Motor" for more information. As to the size of VS pump to purchase, they currently come in two sizes, about 1.6 HP and 3.0 + HP. I would go with the larger HP for your size pool. Since they are self-adjusting, you can scale the HP down to what's actually needed.Reply
Frog Posted: 9/1/2013
I have an inground irregular/kidney shaped pool with 16,000 gallons. It is a saltwater pool with solar heating (2 story house) and infloor sweepers. I have 2 drains ~3 ft apart and 1 skimmer with an avg. ft head of 48 ft. I have a DE filter. My pump size is 2HP A.O. Smith MOD K48N2PA105C4, Volts 230 with a Pentair WhisperFLo Mod WFE-8 2 HP/ Service factor of 1.3 pump. Should I change to a VS pump with less HP and if so which size would be best? I have used energy savings calculators and they say I will only save $70 a year, seems low. 50% of our energy use is running the pool pump ~5 tp 6 hrs a day. Thanks for your help!Reply
MDF Posted: 8/27/2013
Thank you!!Reply
InyoPools Product Specialist Dennis R. Posted: 8/26/2013
MDF - You are correct. For a single speed motor you want to run it as short a time as required. For a VS motor you want to reduce the speed as much as you can and run it for as long as you can at that lower rate. Remember if you cut your speed from 3450 RPM to 1725, you will reduce your energy costs to 1/8 over the same period of time. If a SS pump costs $240 to run a month at 8 hours a day, a VS pump will cost $60 to run at 1725 for 16 hours a day. Both will turn over the same volume of water.Reply
MDF Posted: 8/26/2013
Thanks for the fast response! Ok, I thought I was required to get all of the pool water through in 8 hours. We run our pump continuously, so does that mean we could spread it over 24 hours and plan for bursts of turning it in 8?Reply
InyoPools Product Specialist Dennis R. Posted: 8/26/2013
MDF - Your requirement for 198 GPM is based on running your 95,000 gallons of water through your filter in 8 hours. If you ran the pump 10 hours instead of 8, you could use a pump that had a flow of 160 GPM. There are at least two VS pumps that will generate 160 GPM: the Hayward EcoStar Variable Speed Pump and the Pentair IntelliFlo Variable Speed. Both motors are over 3.75 Total HP. If you ran these motors at half speed [and half flow] for 20 hours, you would reduce your energy cost to 1/8 of your full speed energy cost. See our guide on "How to Save Money Using a Variable Speed Motor".Reply
MDF Posted: 8/25/2013
We have a 25'x 78' rectangular pool with a deep end of 10' and a shallow end of 3'. I calculated this to be about 95,000 gallons based on the formula given in step 1. This leads me to 11,875 GPH or 198 GPM.We have 4 skimmers and 2 main drains, but no other suction features.
I calculated the average feet of head to be 90'.
We had a single speed 3HP pump running 24x7 that just froze up. So we need to replace it.
Question 1. Can we get a variable speed pump?
Question 2. None of the pumps listed in the Hayward table seem to meet these specs. Can you tell me the name of another brand that might meet these specs?
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InyoPools Product Specialist Dennis R. Posted: 8/23/2013
lance - The model number of a pump is sometimes stamped into the shoulder of the pump near the discharge port. If not, try looking on the underside of the strainer cover. A part number is usually stamped there that can be crosschecked to the pump on a parts list.Reply
alex Posted: 8/22/2013
Thank you, very helpful !!!Reply
lance Posted: 8/22/2013
Hi, sorry me again. I think the pool pump is a sta rite however, I cannot find a model number on it at all. Any clue on where it is located? This is actually my mother pool and bought the house a couple of years ago and she didn't get any manuals or information on the pool. I don't know the age of it and I am assuming it's a sta rite based on a picture search I did.Reply
InyoPools Product Specialist Dennis R. Posted: 8/14/2013
lance - You are correct. The pump shaft seal will depend on the type of pump.Reply
lance Posted: 8/13/2013
Thanks so much! Now...the pump shaft seal will depend on the type of pump I have right?Reply
InyoPools Product Specialist Dennis R. Posted: 8/12/2013
lance - For a 20K gallon pool, people will generally use a 1 1/2 HP motor. You actually have a 1.67 HP motor. A pump's Total HP (THP) is measured by multiplying the pump's stated HP by its Service Factor (SF). If you look on the label of your B848 you will see that it has a HP 1.0 and a SF of 1.67. The product of the two numbers is 1.67 which is your pump's THP. I would replace your current motor with the same motor. Remember to replace your pump's shaft seal when you change out the motor.Reply
lance Posted: 8/11/2013
I have a 20k gallon pool with a 1.0 hp SF 165 AO SMITH B848 Pump motor that has died. The pool has 2 returns, 1 skimmer, and 1 drain. My thinking is to replace it with a 1.5 hp AO Smith B2854. Can I do that or should I stay with 1.0 hp? If I replace with the 1.5 hp will I need upgrade the impeller, diffuser and eye seal?Reply
InyoPools Product Specialist Dennis R. Posted: 8/1/2013
Jon - Sounds like your bearings are going again. They may have been misaligned when installed. If you didn't replace the shaft seal, it may be spraying onto the motor. You could definitely go to a 1 HP motor for your size pool and setup. And, if you can afford the initial cost, you should consider a variable speed pump. See our guide on "How to Save Money Using a Variable Speed Motor". They are just coming out with smaller 1 1/2 HP VS pump that would work well for your setup.Reply
Jon Posted: 7/28/2013
Excellent information so far, just a couple of questions. I have 16000 gallon inground with no fountains, just suction vacuum and solar heating as well as gas heater. Currently I have 3/4 hp Hayward super pump that I just changed bearings however its starting to make a squeaking noise from the motor. First question, are my new bearings going again or do you think motor is just dying? Also wondering if i should upgrade to 1hp? I have to keep my pump running 24/7 should look into variable speed or stick to single ? Thanks in advanceReply
Oreshans Posted: 7/28/2013
We have a 1000 gallon, in ground spa that we cannot keep from getting green from one Saturday to the next. Usually, by Wednesday or Thursday, it is green. We have been trying to bring the phosphates under control. We shocked it yesterday and today the phosphates were at 300. A month ago, we drained the entire spa and filled it with new water. We are constantly needing to shock it because the chlorine barely registers even though there are tablets in the dispenser and we have been diligent about keeping the Soda Ash level in range. We are going nuts. The GPM rate is 16.7 and the head is 10. I took a picture of the pump to see what the pump was and found that it is a Magnetek Century 8-77064-03 Pool and Spa Motor. 1081 Pump Duty. theHP is 2.o - .25 The filter is a Hayward, Star Clear Plus,__ __175.
We are at our wits end. It is in our rental and we maintain it but we can't.
Can you make suggestions as to what the problem can be. It acts like the water goes through the inlet and right back out the outlet and never is filtering because the pressure never changes at all. Yesterday, we engineered to parts that close the cartridge filter hold so it fits tightly rather than leaving a space in the center. It seems to have changed the pressure from 28 - 30 after filtering out most of the green algae. It didn't seem like the water was ever going through the filter so we forced it to go through the filter.
HELP, Please....
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InyoPools Product Specialist Dennis R. Posted: 7/23/2013
oyster56 - I don't see a motor replacement at 1.25 THP, but based on your information, you could probably use a motor with 1.1 or 1.0 THP. The 1.1 THP motor is a standard uprated motor, UST1102. The 1.0 THP motor is an Energy Efficient (EE) motor, UCT1102. The EE motor is $40 more but would save you 20% on operating costs. Also since these both are slightly smaller motors than your old one, you will have to buy a smaller impeller. And, for any motor replacements, you should buy a new shaft seal.Reply
oyster56 Posted: 7/23/2013
We have a pool that just about exactly matches your average pool but it has only one drain and one skimmer, which are an average of 30 ft. away from the pool pump. We currently have a A.O. Smith Century Centurion 1 HP motor with an SF factor of 1.25, which has reached the end of its life. This pump motor is on a Jacuzzi Magnum 1000 pump. Is a replacement with THP of 1.25 sufficient or over or under our needs? There are no additional features such as waterfalls using the pool pump's capacity. Although I favour a VS pump for the quiet and the lower environmental impact, given our modest electricity costs and a short swimming season of less than three months, we will probably stay with a single speed pump motor. Thoughts? Suggestions? Thanks.Reply
InyoPools Product Specialist Dennis R. Posted: 7/18/2013
Mike - Your pool holds about 10,000 gallons of water. A 1 1/2 HP pump should be sufficient to handle circulation for this size pool and your waterfalls.Reply
Mike Posted: 7/17/2013
I am having a 27x12 fiberglass pool installed. The deep end being 5'. I am also having a three tier waterfall with 1 shear decent in the middle and 2 18" shear decents on either side. I am having a 1 1/2 hp pump installed. My question is should I get a second pump to run the waterfalls. The pump will be located 15' from the skimmer.Reply
InyoPools Product Specialist Dennis R. Posted: 7/17/2013
MM - For a head of 11' you would need a 1/2 HP Hayward Super Pump that would provide 55 GPM. This is overkill but this is the smallest pump we sell. For a head of 67' the charts show you would need a 1 HP Hayward Super II Pump (different class of pump) which provides 35 GPM. The next lower pump, 3/4 HP, is right on the edge of providing 19 GPM for 67' of head and the manufacturer recommends going up to the next level.Reply
InyoPools Product Specialist Dennis R. Posted: 7/16/2013
Bjtex - Yes, you could use a 1 1/2 HP pump but you're on the edge. You could hedge your choice a little by getting a 1 1/2 HP pump with a SF of 1.10 or 1.25 to get a slightly higher THP. THP = HP x SF. If you are concerned about operating cost and can afford the initial pump cost, you should look at buying an Energy Efficient (EE) pump or a 2 speed or variable speed pump.Reply
MM Posted: 7/16/2013
I am building a small inground splash pool of size 13' X 8' with 3' depth. This will contain 2300 gallons of water. I have two options for placing the pump ; one nearby with head of 11' and the other at a distance with head of 67'. What capacity of pump and also the pump size is recommended in each of the two cases with flow of 19 GPM? Appreciate urgent help. ThanksReply
Bjtex Posted: 7/14/2013
I have a 30K In-ground pool with 40 ft of head and 2 in water lines Could I use a 1.5 hp pump. I currently have a 10 yr. old 2 hp pump that's very costly to run...Thanks
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InyoPools Product Specialist Dennis R. Posted: 7/8/2013
volts/amps/watts - A pool motor's volts/amps/watts are generally defined by the HP of the motor. With little exception, pool motors use either 115V or 230V. That is defined by the power available at the house. Amps (and Watts) are directly related to HP. The more HP a motor has, the more Amps/Watts it will use. Some EE motor are designed to be more energy efficient than their stand counterparts and might use 20% less Amps/ Watts for the same HP.Reply
InyoPools Product Specialist Dennis R. Posted: 7/8/2013
Glenn- Your main limitation is your pool's pipe size of 1 1/2". For your volume of water you could probably use a 2 THP pump but your piping should not use anything over 1 1/2 THP. Note that's real or Total HP [THP] which is the product of HP and Service Factor [SF] - see motor label. For example, a motor with a labeled HP of 1.5 and a SF of 1.4 has a real THP of 1.5 x 1.4 or 2.1 THP. If you have the option of changing out your piping for 2" or 2 1/2" pipes, you could use the larger pumps.Reply
Anonymous Posted: 7/7/2013
I have a 14 x 28 rectangle pool, I know I need a 1hp pump, but how do I know how many volts/amps/watts ?Reply
Glenn Posted: 7/6/2013
Please help,I have a 24x48 inground liner pool (50,000gallons). I have to run the pump 24/7 to keep clean. There is 2 stair returns, and 2 returns in shallow end for a total of 4 (2 lines leave pump and turn to 4). I then have 2 skimmers and one bottom drain. All the pipes are 1.5 inch. 500lb sand filter and a 1hp motor. What changes do I need to do so I don't have to run pump all day and night and keep a clean pool? Any advice would be super helpful! Thank you.
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InyoPools Product Specialist Dennis R. Posted: 7/2/2013
anna - This guide provides an estimate for a typical pool. With your pool's extra returns and drains, you could go with a 1 1/2 THP pump. A 2 THP pump is probably too big. However, if you have 2" piping in your suction and return lines, you could go with a 2 THP pump and if you find it's too much you could back it off by substituting a smaller impeller. Note make sure you are looking at real or Total Horse Power (THP) which is the product of HP and Service Factor (SF) when selecting a pump size. Some pumps labeled 2 HP can actually be 2.5 THP if the SF is 1.25.Reply
anna Posted: 7/1/2013
I have rectangular pool with 4 drains along the bottom every 12 feet or so. My pool is 52' long by 8' wide by 6' deep. It has around 20 returns going all the way down both ends of the pool and 1 at each end. I currently have a 1 hp pump and going by your calculations, that is exactly where I should be but the returns at the far end of the pool barely have a drizzle coming out of them. I also get terrible suction while vacuuming the pool. I want to go to a 2 hp pump just because I am afraid of not going big enough. Do you think that a 1 1/2 hp would be enough?Reply
InyoPools Product Specialist Dennis R. Posted: 6/29/2013
terry - For your size pool with a spa and water features and 2" piping, many people use a 2 HP pump.Reply
terry Posted: 6/28/2013
i have a 20 x 40 33,000 gal. inground pool what size pump do i need ?Reply
JJ Posted: 6/22/2013
I thought that determining pump head simplisticly was to measure return pipe runs from the pump to the pool instead of measuring pipe runs from skimmers and drain. If I use the measurement from skimmer and drain my head is 20; if I use the measurement of return lines my head is somewhere around 50-60. I guess I'm missing something here.Reply
InyoPools Product Specialist Dennis R. Posted: 6/14/2013
Steelers7 - Sounds like going to a 1 1/2 HP pump is a good option. Your 600 # Sand filter will support the increased GPM flow and your pool is sized for it. Also, this size motor will support the addition of a new waterfall. When you move the pump and filter out 20', make sure that the wiring from the circuit breaker to the pump is at least 14 gauge for 230V or 12 gauge for 115V supply power. Consider buying an Energy Efficient (EE) pump for operational cost savings of 20%.Reply
Steelers7 Posted: 6/12/2013
Just want to know, I have a 17k inground pool with a heyward 600 lb sand filter. I want to later add a water fall using the pool water and possibly move the pump and filter approx. 20' away from where it is now. It is approx. 8' from the skimmer. Can I use a 1-1/2 hp pump wothout damaging anything right now as it stands. I currently was using a 1 hp until the motor gave out. Help.Reply
InyoPools Product Specialist Dennis R. Posted: 6/2/2013
Jc - We generally recommend a pump with 1 1/2 Total Horse Power (THP) for a pool your size. THP is the product of HP shown on the motor label times its Service Factor (SF) printed on the label.Reply
InyoPools Product Specialist Dennis R. Posted: 6/2/2013
sendmiller - We would also recommend a 1 1/2 THP pump for your size pool. Be aware that when you are looking for a 1 1/2 HP pump you need to look at Total Horsepower (THP) which is the product of HP and Service Factor (SF). If you look at your motor label, your HP might read 1 HP and the SF might read 1.5. Your motor's THP would be 1 x 1.5 or 1.5 THP.Reply
Jc Posted: 6/2/2013
Hi im trying to change my pump & piping on my inground pool..my pump is rusted i cant see the pump info..here's my pool info i got 20k gallons 1 skimmer & 1 return ,1.5" pipe will change to 2"...i measure the feet of head about 20 feet & will put three 90 deg fitting once change...my filter is sand w/ filtration area of 2.6 ft , filtration rate of 20 gpm/ft,filtration & backwash design flow rate of 52 ..pump info's 3/4 hp w/true hp of 1.22 @ max,feet of head of 22 & flow rate of 50 gpm.. Or 1 hp w/true hp of 1.65 @ max,feet of head of 24 & flow rate of 54 gpm..do i go 3/4 hp or 1 hp?...thanksReply