Swimming Pool Blog

New Pool Pump Installation

by Rob Cox, July 6, 2010

New Pool Pump Installation

At the heart of your pool's circulation system is the pool pump, making filtration and circulation possible. A tireless workhorse, running in the hot sun, day after day - eventually the motor will fail. The industry average for motor life is 8 years, so it's likely that you may replace it more than once.

Many times, the pump itself won't need replacement, only the motor, and surely some of the gaskets and baskets used on the "wet end" of the pump. At times, however, the cost of repair can exceed the cost of pump replacement -or- an even better reason for pump replacement is to install a pump that is more energy efficient.

With regards to energy efficient pool pumps, most new pumps nowadays are equipped with energy efficient motors. You can take several directions:

  1. With careful review of the pump flow charts, you may be able to install a new pump with lower horsepower, but higher flow rates. Using a pump of a lower horsepower will draw fewer amps, resulting in lower energy consumption.
  2. Installing a two speed pump will allow you to operate most of the time at only 1/8 horsepower, using full speed for 3-6 hours per day. Two speed pumps utilize four wires, so you will need to re-wire and/or purchase a new time clock.
  3. Installing a variable speed pump, like the Intelliflo, saves money by self-optimizing it's own horsepower, and thus amp draw.

This article however, is not about Pool Pump Selection, here we focus on Pool Pump Installation. You've already done your homework, selected your new pump, and it just arrived. So, what's the next steps in replacing an inground pool pump? back of motor

Tools Needed: Large Pliers, Screwdriver, 5/16 nutdriver, Hacksaw, Couplings or Unions.

  1. Shut off power at the circuit breaker. If you have a timeclock, look in the viewfinder to make sure the gears have stopped turning. Or use a multi-meter to make sure that you have flipped the correct breaker.If your system is below water level, close the valves to keep water from soaking your socks!
  2. Remove the wiring cover on the back of the motor, and loosen all 3 wires (4 wires if you have a two speed motor). Loosen the conduit connector on the outside of the motor, so that you can pull the wires out of the motor. Your pump may also have (should have) a bare copper wire connected to the motor. This is a bonding wire, remove the wire from the bonding lug and bend it out of your way.
  3. Break out the Hacksaw. Choose your cut location wisely on the pipe coming into the pump, and the pipe coming out of the pump. Using unions will allow you to remove the pump for service easily in the future, or for winter storage indoors. Unions are also cheaper now than they used to be, around $5 each, compared to $2 each for regular slip x slip couplings. If using couplings, choose a cut location that will allow you to cut again in the future if needed. If there is no room to cut, without cutting out expensive and still functioning valves, consider moving the pump further back, away from the valves. Make clean, vertical cuts through the pipes, and remove any pvc burrs.
  4. Break out the large Channel Lock pliers, or strap wrench to unthread the pipes out of the existing pump. If these plumbing fittings were not leaking, you can reuse them. If the the pump was leaking air through the intake or leaking water from the outtake of the pump, you should replace the threaded fittings, as it is probable that the threads have shrunk. These fittings are commonly called MTA's or male threaded adapter, and can be obtained at a home store or plumbing supplier.
  5. Thread the MTA's into the new pump. Use 3 wraps of Teflon Tape, in a clockwise fashion, covering the threads. Adding some silicone to the threads first, or blue RTV can give a little extra seal. Thread them hand tight and then go another full turn with the wrench. Overtightening may crack the pump housing!
  6. Replace the wires onto the new pump. It's a bit easier to do this before plumbing the pump in, as you can stand the pump up onconsult your pump dimension chart first the front end, for easier access to the back of the motor. (make sure power is still off!) Connect the ground wire to the green ground screw. The other two power leads will go to either terminal screw A or B, doesn't matter which one. Important to NOTE: Your new pump, if it has a reversible voltage motor, 115/230, will come wired for 230 volts. If you are only using 115 volts, follow the diagram on the motor to switch from High Voltage to Low Voltage
  7. Line up the new pump to the existing pipes. If you have changed pump models or manufacturers, the height of the incoming pipe and the setback of the effluent pipe probably won't line up exactly. If your new pump sits lower than the old, find a brick or something solid (wood will rot eventually) to raise the level of the pump up. If the new pump sits higher than the old pump, and you cannot "lower the ground" then you will need to get creative with your plumbing with some 45's to bring the incoming pipes higher. This can be avoided during pump selection, by checking the diagrams first, try to purchase a replacement pool pump with similar dimensions.
  8. Make the plumbing connections. Use pvc primer first on both the fitting (union or coupling) and on the pipe. If the pipe has dirt and gunk on it, scrub it good, or use emory cloth or wet/dry sandpaper to clean it up before priming. Within 30 seconds, glue both the fitting and the pipe liberally (on one side at a time). Push the fitting on the pipe to full depth, with a slight twisting motion. Hold firmly in place for 5-10 seconds. 
  9. Fill the pump with water. Check for leaks around the base of the pump. Open any valves that were closed before installation.
  10. Fire it up! Flip on the breaker first, and reset the timeclock to the correct time. Cautiously turn on the pump, if it sounds loud, or grumbly or - if it starts smoking...shut the pump off quickly. If it starts smoking or sparking, this usually means that you are connecting 230V into a motor wired to accept 115V. Might have burned it out! It could also mean that wires are crossed or touching each other in the rear of the motor. Not to scare you, this rarely happens, and if you follow these steps above, you should have no problem installing your own pool pump.


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