Running A Pool Pump At 1000 RPM
In this article we are going to examine a Pentair SuperFlo variable speed pool pump operating at 1000 RPM to see both the flow rates as well as the electrical consumption for this pump under these conditions. For this bench test the pump was installed with a 240 Volt electrical supply and 1.5" plumbing was used for both the suction as well as the discharge pipes. It is important to understand that every swimming pool plumbing installation is unique and this means the power consumption and volume of flow that you might experience on your pool will be different from the exact values that you see here. This is one of the main reasons why you should consider buying and installing a flow meter on your plumbing system so that you can monitor your own rate of water flow under various RPM conditions.
It is important to watch the attached video to the end as running your pool pump around the clock at 1000 RPM is not going to be sufficient for most pools. Even if you were to achieve the total flow rate for filtration that you need it is very likely that the rate of flow would be too low for peripheral items like heaters and salt water chlorinators to function. Even if your pool is very basic and does not have peripheral items that require certain flow rates, even the skimmer in your pool will fail to function properly, or at all, without sufficient suction to help create the vortex motion that enables your skimmer to work properly. If your skimmer does not collect debris then it is very likely that you will end up with more organic debris that saturates and ends up on the bottom of the pool. In addition to making more work for you, this serves to increase the rate at which your sanitizer depletes in the water which results in more chlorine being needed, as well as more subsequent chemical corrections. Saving money on electricity running your pool pump is great, but not at the expense of unmanageable or dirty pool water that uses far more chemicals than it should be using.
How much water does a pump move at 1000 RPM? - This is a dynamic question with a lot of variables. Every model of pump is different, and every swimming pool installation is unique. This test looks at a 1.5 horsepower Pentair SuperFlo VS pump on a bench test installation (which means little overall resistance to flow) in which the pump is running on 1.5" plumbing. The instrumentation for this testing shows the flow rate at 1000 RPM to be between 15 to 18 gallons per minute. Going with the conservative estimate of 15 GPM, this would be 900 gallons per hour, or 21,600 gallons based on a 24 hour run schedule.
How much power does a pump use at 1000 RPM? - Again this is a dynamic question that can only be answered effectively with specific examples. In this bench test the Pentair SuperFlo VS pump, with a 240 Volt electrical supply, consumed about 139 Watts, or 0.139 kW when running at 1000 RPM. For every hour of operation the pump will use 0.139 kWh (kilowatt hours) of electricity which you would then multiply by the electrical rate that you pay. The nationwide average of 13 cents per kilowatt hour when applied to this test means this pump costs $0.018 per hour to run like this, and the 24 hour running cost would be just over $0.43 total.
Under fifty cents per day and still able to filter over 20,000 gallons of water sounds like a great thing, and it is, but the question of how to filter pool water properly is more complicated than simply setting your pump to 1000 RPM and letting it run around the clock. The first question you need to answer is whether your pool moves any water at 1000 RPM or not. You will likely not show much, if any, pressure on the filter gauge at this low of an RPM. At best you can feel for flow at the pool returns, or look for flow in the skimmer suction, but without a flow meter you are relegated to some guess work when it comes to flow rates. Supposing you feel, or know, that you have some significant flow (anywhere from 10 to 20 GPM) when you are running your pump at 1000 RPM, this is only part of the total filtration equation.
It is not a good idea to run your pump on 1000 RPM 24 hours per day, but this is actually close to how you get the most out of a variable speed pump in terms of electrical savings. You do want to run your pump for many hours per day, probably most of the day, at 1000 RPM (or a similar low RPM which is able to realize between 10 to 20 GPM) as this will allow you to filter a great deal of water for an amazingly low electrical cost. You however still need to run your pump at higher RPM speeds to help satisfy the flow requirements for any peripheral items you have like in-floor cleaning systems, salt water chlorinators, gas heaters, electric heat pumps etc. as well as having periods of higher flow rates for better movement of the pool water and functioning of your skimmer.
This is why you should not run your pool pump at 1000 RPM only, but incorporating long periods of filtration time at low RPM's is certainly part of an effective (and efficient) filtration schedule. This article also highlights the importance of flow meters and how they help to take the guess work out of flow rates - something that is critically important if you want to get the most return out of your investment in a new variable speed pump. For more videos like this that help teach you, and show you, how pool pumps work and how to get the most out of yours, please be sure to subscribe to my YouTube channel.
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