So, you’ve decided to replace the pool pump. After deciding on standard or variable speed, and placing your order – what’s next?
After the box arrives on the doorstep with your new pool pump, open it up and pull out the owner’s manual. Turn to the installation section and read it carefully before beginning.
Assemble your tools and supplies needed for a pump replacement:
- Large Channel type pliers or Pipe Wrench
- Hacksaw, or small power saw
- Teflon Tape and Silicone sealant
- PVC glue and PVC primer
- Various PVC fittings, PVC pipe
DIfferent Pump, Different Height
If you are installing a different brand or model of pool pump, it will likely have different port measurements, called pump dimensions.
These are the measurements from the ground to the center line of the incoming port, and the distance from the front of the pump to the center line of the outgoing port. You can measure your current pump ports yourself, or look up the dimensions in your old owner’s manual.
Many pumps have bases that are adjustable, to raise or lower the pump. If your new pump sits lower than your current pump, you can raise it up on a paver, no problem.
But, if the new pump sits higher than the incoming pipes, you usually can’t lower the equipment pad. What you can do is cut the incoming vertical pipes for the skimmers and main drain, and use long couplings to raise the manifold about an inch. You can also use two 45’s on the incoming horizontal pipe, to raise it up 2-3 inches.
Removing the Old Pump
After assembling all needed fittings, pipe and supplies to plumb and wire the new pump in place of the old, you can begin by cutting the pipe coming in and out of the pump. Leave enough clear pipe available to attach a coupling or union.
With the power off at the breaker, remove the rear pump motor cover, or access plate. You can tip the pump up, now that the pipes are cut, to gain a better view of the wires inside. Be careful not to stretch and bend flexible conduit too much however, older wire harnesses can break.
Locate the 3 incoming wires, two power leads and one ground wire. Remove them carefully with needle nose pliers or a nut driver in some cases. With pliers, loosen the large nut on the conduit fitting, to loosen the conduit and pull the wires out of the old pump motor. Unscrew the conduit fitting from the old motor and place into the new pump motor.
Disconnect the bonding wire, a bare copper wire that you should find attached to the motor, on a bonding lug.
Pool Pump Wiring
Position the new pump in the best location, which may be different from the former position. I like to wire the pump first, before plumbing, as it makes it easier to wire the pump when you can tip it up on end.
Feed the wires through the conduit fitting and tighten the large nut. Reconnect the wires into the motor, and the ground wire. It doesn’t matter which power wire goes to which power terminal.
Inground pump motors that are reversible (accept both 115V or 230V) will always be shipped ready for 230V. If you want to switch to 115V, refer to the wiring diagram on the motor. Most inground pools will use 230V for the pump. If you are unsure, refer to the wiring diagram on your existing motor, to see if it was set up for 230 or 115 volts.
Aboveground pumps will come with a cord to plug in to a grounded outlet, 115V, and are not reversible to run on 230V. Larger inground pumps of 2 hp or more, or variable speed pumps, are also not reversible to 115V, and will always require 230 volts.
Pool Pump Plumbing
If you are replacing with the same pump, the pipes will match perfectly, and you can simply reuse the threaded male adapters (MTA’s) screwed into the old pump, and use 2 couplings or unions to rejoin the pipes together. Done!
Some pumps come with union fittings (a nice feature). Either way, next step is to screw in the fittings to the incoming and outgoing ports of the pool pump.
Without unions, use two MTA fittings. Spread some silicone (I like Blue RTV) into the threads, and then wrap the threads with Teflon tape, wrapping all threads 3 times, in a clockwise direction. Hand tighten the prepared fittings into the pump ports, and then use large pliers to turn no more than 1-1/2 more turns. Don’t overtighten, it may crack the pump.
Level the pump to the incoming and outgoing lines, and make the connection into the unions or use a coupling and a short section of pipe. Measure twice, cut once! Dry fit all of your connections first, just to make sure that the measures are good, and the plumbing design makes sense.
Use PVC primer or cleaner just before gluing PVC pipes and fittings. Quickly after gluing, press together and push pipes deep with a twisting motion. Hold for 10 seconds and then wipe up any drips with a paper towel.
Make sure you are using pressure fittings and not drain fittings, which have a more shallow depth to the fittings. Pool fittings have about 1.5″ of depth for gluing the pipe deeply.
You can bend and push pipes a bit while making connections, there can be an inch of play in most directions. If you quickly realize you made a plumbing mistake, or if the glue joint seems weak, you have a few seconds to pull apart the connection if needed.
With your new pool pump plumbed in place, you can reconnect the bonding wire. Attach the bare copper wire to the bonding lug on your new pump motor. Now fill the pump basket with water, open the valves, and test out your new pump!
InTheSwim Blog Editor