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Swimming Pool Pump Tutorial

The information provided on this page is intended as a guide to help you determine what pool pumps are suitable candidates for your pool, however we strongly suggest that you consult with a certified pool professional before you make the final decision. Also there may be local municipal or city laws that may affect what kind of pool or spa pump can be used in your pool. Contact your local Department of Health for more information.

Pool Volume

    Knowing the volume of water (in gallons) in your swimming pool is important in all areas of swimming pool maintenance and chemical applications. It is also vital to know when choosing the appropriate pool equipment for your swimming pool.

    The volume of your pool is a calculation of your swimming pool's dimensions multiplied by your pool's average depth. The following chart is designed to help you estimate the gallonage in your style swimming pool. We have also posted many of the most common dimensions with their calculated gallonage.
    • Average Depth = depth at the deep end + the depth at the shallow end / 2.
    • Rectangular Pools - Multiply length x width x average depth x 7.5 = gallons
    • Round Pools- Multiply diameter x diameter x average depth x 5.9 = gallons
    • Oval Pools - Multiply full width x full length x average depth x 6.7 = gallons
    • Irregular shapes and size pools capacity should be determined by your pool builder or specialist.
    • If your pool has sloping sides, multiply your final figure of gallonage by 0.85 for correct gallonage.
    Above Ground Pools (48" deep)
    Pool Size US Gallons 6 Hr. Turn Over 8 Hr. Turn Over 10 Hr. Turn Over
    12 ft. Rnd 3,200 9 7 5
    15 ft. Rnd 5310 15 11 9
    18 ft. Rnd 7646 21 16 13
    21 ft. Rnd 10,407 29 22 17
    24 ft. Rnd 13,593 38 28 23
    27 ft. Rnd 17,204 29 22 17
    28 ft. Rnd 18,502 51 39 31
    30 ft. Rnd 21,240 59 44 35
    12 ft x24 ft Oval 6,400 18 13 11
    15 ft x24 ft Oval 8,000 22 17 13
    15 ft x 30 ft Oval 10,000 28 21 17
    18 ft x 33 ft Oval 13,000 36 27 22
    Inground Pools (Average Depth 5 Feet)
    Pool Size US Gallons 6 Hr. Turn Over 8 Hr. Turn Over 10 Hr. Turn Over
    12 ft x 24 ft 10,800 30 23 18
    14 ft x 28 ft 14,700 41 31 25
    15 ft x 30 ft 16,875 47 35 28
    16 ft x 32 ft 19,200 53 40 32
    16 ft x 34 ft 20,400 57 43 34
    16 ft x 36 ft 21,600 60 45 36
    18 ft x 36 ft 24,300 68 51 41
    20 ft x 40 ft 30,000 83 63 50
    20 ft x 44 ft 33,000 92 69 55
    24 ft x 44 ft 39,600 110 83 66

    Determine the Pool Turn Over Rate:

    • The turn over rate is how many times the pump circulates the entire pool volume through the filter system in a 24 hour period.
    • The Turn Over Rate for public/commercial pool = 6 hours.
    • The Turn Over Rate for residential pool = 8 to 10 hours.

    Determine the Desired Flow Rate (DFR) in Gallons Per Minute (GPM)

    • Desired Flow Rate DFR = Gallons of water in pool / Turn Over Rate* / 60
    • Example: Desired Flow Rate DFR = 20,000 gallons / 8 hrs / 60 = 41.67 gallons per minute (residential pool)

    Determine TDH (Head in Feet):

    • The total dynamic head in feet of water is the amount of pressure resistance in the pool piping (pipe size, 90 degree turns, etc.) the pump has to overcome to push water through the pipe.
    • The easiest way to calculate the TDH in a pool is to read the pressure gauge (PSI) readings in a cleaned and running pool filter and multiply the PSI by 2.31.
    • The formula is TDH (feet) = (PSI x 2.31)

    Read Pump Capacity Chart:

    • Select the pump by following the TDH line across the chart until it crosses your GPM reading. This will give you an idea if you're operating with a proper pump size.
    Pump Capacity Table
    Model HP Head in Feet Shut-off
    20' 30' 40' 50' 60' 70' 80' 90'
    Gallons Per Minute (GPM)
    PKH2RA6D-101L 3/4 64 52 44 50 - - - - 55'
    PHK2RA6E-102L 1 85 75 62 50 30 - - - 65'
    PHK2RA6F-103L 1-1/2 100 90 80 70 52 30 - - 72’
    PHK2RA6G-104L 2 - 105 95 82 70 60 32 - 85’

    Safety Guidelines for Pools and Spas

    While the suggestions outlined will make pool and spa use safer and more enjoyable, no one can guarantee that accidents will not happen.The precautions outlined cover only the basics. This suggestions are not intended to replace instructions you receive from your owner’s manuals or pool professional. By using a little common sense, taking proper safety precautions and having your pool professional do regular maintenance and safety inspections, your pool and spa mechanical equipment should provide safe and trouble-free enjoyment for years to come.

    Hazard #1- Pump suction (from the main circulating pump)

    Your pool or spa’s main circulating pump pulls in water by means of a strong vacuum through the main drain. The vacuum is so strong that anyone lying on an 8” diameter main drain while the pump is running could be held down on the drain by a force of up to seven hundred pounds (that’s right, 700 pounds). This is enough force to trap adults or children underwater, or even to eviscerate them. Stay off the main drain! Have your pool professional examine your pool or spa for the following points:
    • There must be at least two suction outlets from the pool to the main circulating pump. Each outlet must have a cover fastened down with screws. Either one of these outlets should be able to supply the pump by itself without exceeding the flow rating of its cover. (Many above-ground pools use the skimmer as the suction outlet and have no main drain; these pools don’t require a second suction outlet.) Read the pump owner’s manual for flow requirements for your installation.
    • All suction outlet covers (for instance, grates, anti-vortex covers, etc.) must be designed so that they won’t trap body parts or hair, and must be certified by a nationally recognized testing laboratory. Plastic deck and drain covers may deteriorate and crack or break from exposure to sunlight or weather. Routinely replace them every 3-4 years.
    • An emergency shut-off switch for the pool circulation pump and the spa jet pump should be in an easily accessible, obvious place near the pool or spa. Bathers should know where it is and how to use it. Use the switch in case of emergency.
    • Most pool cleaners and all pool vacuums use the pump suction to clean the pool. Because of the strength of the suction and the possibility of entrapment underwater, keep everyone out of the pool during cleaning or vacuuming. Read the cleaner or vacuum owner’s manual for safe operating information. Never play with the pool cleaner, the vacuum, or their hoses – they are not toys.

    Routine Maintenance Tasks

    Routine maintenance helps keep your pool and spa system operating safely and efficiently. Follow a regular check-off procedure for the safety-related items listed, or have your pool professional perform the following tasks regularly:
    • Make sure that each suction outlet has a cover that is installed correctly, screwed down, unbroken, and certified for that application.
    • Make sure that all skimmer covers are in place, screw-fastened and unbroken.
    • Make sure that the filter pressure gauge is in good working condition and that the filter pressure is within the operating range specified in your filter owner's manual.
    • Make sure that filter O-rings are sealing properly and in good condition.
    • Bleed off accumulated air from the system.
    • Empty the skimmer baskets and the pump strainer basket of debris.
    • Remove any debris or obstructions from the main drain cover.
    • Remove obstructions and combustibles from around the pump motor air vents.
    • Make sure that all chemicals are properly stored (away from equipment).
    • Make sure that the heater is functioning properly.
    • Make sure that there is no gas smell around the heater.
    • Make sure that all grounding and bonding wires are connected and in good condition.
    • Make sure that all wiring connections are tight and clean and that all wiring and electrical equipment are in good condition.

    Hazard # 2- Compressed air trapped in the system

    Water under pressure doesn’t present much of a hazard. But the piping and filtering systems on pools and spas can trap and hold large bubbles of air until they build up enough explosive potential to blow the tops off of filters, strainers, and separation tanks. The owner’s manual for your filter, separation tank, and pump will tell you how to safely bleed the air out of your filter system. For safety’s sake, review the following points:
    • Read the owner’s manual carefully to learn how to operate your filter system safely. Never try to adjust or service your pool or spa filter unless you have read the owner’s manual and understand how to release all pressure from the system (shut off the power and release the pressure first).
    • When starting up the system after a period of non-use (for instance, after a winter shut-down), read the start-up instructions in the owner’s manuals for the equipment involved so that you can purge all the air from the system before it builds up to dangerous pressures.
    • Never connect your pool or spa filter system to a household water system – the pool equipment is designed to run at much lower pressures and may split or burst if subjected to household water system pressures.
    • To avoid a dangerous pressure buildup in the filter, make sure that any shutoff valves downstream of the filter always remain open during system operation.
    • The pool skimmer may be sucking air (“vortexing”) as well as water. This can pull a large amount of air into the filter system, and should be corrected by raising the pool water level, reducing the flow of water through the skimmer or both.
    • Vacuums and cleaners can also suck air for brief periods of time. Before you use a vacuum, submerge the hose completely and let it fill with water before connecting it to the pump suction outlet. This will minimize the amount of air taken into the system.

    Routine Equipment Safety Check List:

    • Is there a complete, readable Owner’s Manual kept handy for each piece of equipment?
    • Are Skimmer Deck Covers NSF Certified and all Suction Fittings and Main Drain Outlet Covers IAPMO certified as anti-entrapment and anti-hair-entanglement?
    • Are Skimmer Deck Covers and Main Drain Outlet Covers in place and screwed down?
    • Are Skimmer Deck Covers and Main Drain Outlet Covers deteriorated, cracked, or weathered? If so, replace them. (On outdoor pools, all Plastic Skimmer or Drain Covers should be replaced every 3-4 years, especially in the “Sun Belt.”)
    • Are Skimmer Baskets clean and in place?
    • Are Filter Tank Clamps and Bolts in place, in good physical condition, and correctly tightened? (Don’t try to adjust clamps while the filter is under pressure.)
    • Are Filter Tank O-Rings sealing properly?
    • Are Filter Tank Pressure Gauge and Air Release Valve in place and working?
    • Is Pool Heater area clear of leaves, flammable material, and debris?
    • Are Heater, Vent Pipe, and Gas Line in good physical condition?
    • Is the entire Pool area free of any smell of gas?
    • Is all visible Electrical Equipment and Wiring (including pool lights and niches) in good physical condition?
    • Do Ground Fault Circuit Interrupters (GFCIs) test OK? (Most GFCIs have a “test” button; see the instructions with the GFCI.)
    • Are Motors, Equipment Rooms, etc., clear of leaves, debris, and combustibles?

    Hazard # 3- Fire, explosion, or asphyxiation

    LP gas (Propane) and natural gas are safe fuels as long as they are used correctly. Read your heater owner’s manual carefully, and remember that gas heaters require a trained technician for service and repair. Remember that gas is highly flammable, and that LP gas is heavier than air – it will collect in low spots. If you suspect a gas leak or smell gas, immediately clear the area and call the gas company from a telephone that is away from the area of the suspected leak. If you suspect a problem with your heater, don’t take chances by trying to fix it yourself – call your heater professional or the local gas company. Have your heater professional verify these points about your installation: Make sure that there is no leakage of exhaust gases into any building. This is especially important if the heater is installed indoors. Improper venting or damaged or rusted-out venting can cause serious injuries, illness, or death from carbon monoxide poisoning
    • Your installation should comply with the requirements of the local and national codes that apply.
    • The heater exhaust vents should be located away from windows, air condi-tioners, or roof overhangs so that exhaust gases (which are poisonous) will not enter any buildings in the area. Check with your local building inspector for regulations concerning the location of heater exhaust relative to buildings.
    • If your heater is located indoors, review the venting information in the heater owner’s manual and, again, make sure that all vent pipes, air intakes, gas line installations, etc., meet all local and national code requirements.

    Hazard # 4- Electricity

    Mixing electricity and water is always hazardous. In a pool or spa situation, underwater lights, deck lights, the motor on the circulating pump, or any other accessory requiring electricity may pose a safety threat to people in the water if the wiring is incorrect or faulty. Read the owner’s manual for each piece of equipment to get information about electrical requirements. To make sure your pool or spa is electrically safe, ask your pool builder or professional service person to verify these points:
    • Ground Fault Circuit Interrupters (GFCIs): The power supply circuit for each piece of electrical equipment should include a GFCI for protection against tiny – but dangerous – leaks of electricity to ground (‘ground faults’). If these tiny ground faults travel through the human body, they can damage the nerves controlling the heart and cause cardiac arrest (heart failure).
    • GFCI will sense ground faults and disconnect the power supply. This protects you from a dangerous and possibly fatal electrical shock.
    • Codes: All electrical equipment and wiring must meet the requirements of the local and national codes which apply.
    • Grounding and Bonding: All electrical equipment must be grounded. All metal objects (ladders, diving platforms, etc.) must be electrically bonded together.
    • Extension cords: Never use extension cords around a pool or spa or to supply power to pool or spa equipment. If they get wet, it’s an invitation to a shock – possibly a fatal shock.
    • Pool drainers: A drainer must always be plugged into a GFCI-protected outlet. Because of the danger of electrical leakage from a drainer to the pool water, never get in the water when a drainer is running, and never put an aluminum vacuum handle (or any similar object which could conduct electricity) into the pool while a drainer is running in the pool.

    Spas and Hot Tubs

    • A spa should always have dual suction outlets to prevent entrapment (see Page 10, “Pump Suction”). All tub suction fittings should be certified to meet the current ASME/ANSI Standards that apply.
    • Keep the water temperature in your spa below 104°F (40°C)
    • Age or health conditions (especially pregnancy) may require a lower temperature; consult a physician for more information. If you’re not sure, start at a lower tempera-ture and gradually increase it, but don’t go above 104° F (40° C)
    • Keep an accurate thermometer in the spa; check the temperature before getting in.
    • If you are using alcohol or drugs (including medications), don’t use the spa or hot tub. The combination of hot water and either alcohol or drugs (or both) can cause dizziness, falling, unconsciousness, or a heart attack.
    • A long bath in hot water may cause hyperthermia (too much heat in the body) which can be fatal. Some symptoms of hyperthermia are: • Nausea • Dizziness • Fainting If these symptoms appear while you are in the spa, GET OUT AT ONCE! Cool the body quickly with cold towels or a cool shower. Call a doctor if the symptoms do not go away.
    • Letting the spa jet pump run at high speed overnight with the spa covered can heat the water in the spa to extremely high temperatures, from the friction of the water flowing through the pump and piping system. This can scald you and may cause spa shell failure and a flood of hot water. Turn off the jets whenever the spa is not in use.
    • Never alter the electrical cord or plug on the spa system. In particular, never cut off a 20-amp plug and replace it with a 15-amp plug. Check the spa’s data-plate to be sure that the system’s electrical requirements do not overload the supply circuit’s capacity.
    • Do not use an extension cord to connect a spa system to an existing electrical outlet. A spa system must operate from a GFCI protected circuit or outlet which is dedicated to that spa only. If in doubt, consult a licensed electrician.

    Pool/Spa Chemical Storage and Use

  • Store water test kits in a cool, dry place, out of the reach of children. Follow the kit manufacturer’s safety instructions – test reagents contain dilute acids and caustics that may cause chemical burns or skin irritation. If you get any of the test chemicals on your skin or in your eyes, flush the exposed area with water. Get medical help for chemicals in the eyes.
  • Store pool chemicals away from the pool/spa environment. Sanitizing chemicals (liquid or dry) and acid solutions that are stored in enclosed areas without sufficient ventilation give off fumes (even from closed containers) that may cause corrosion and deterioration of electrical terminals, wiring, and metal components. Deterioration of electrical components may create shock hazards or cause the equipment to fail.
  • Read all chemical usage safety instructions and be familiar with emergency procedures, so that in the event of a chemical spill or accident you will be able to act quickly. Put on protective clothing and eyewear before handling chemicals. Do not breathe concentrated chemical fumes.
  • Never mix chlorine or bromine with acids. Never mix chlorine with bromine. Always dilute chemicals by adding the chemical to the water. Never add water to the chemicals.
  • Never pour undiluted chemicals into the skimmer deck opening or into the pool. Dilute the chemicals before adding them to the pool water, and then distribute the solution around the perimeter of the pool.
  • Always be sure that no swimmers are in the pool when you are chemically treating the pool water.

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