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Pumps & Motors (cont.)

How to INSTALL an entire new pump


Plumbing in a new pump motor...


Cut the pipes going into the front of the existing (old) pump, and the pipe coming out of the top. Important: Choose your cut location so as to allow room on either side of the cut to glue on a repair coupling. Remove the wires and the conduit adapter from the rear of the motor. Remove the MTA fittings threaded into the front and top of the old pump. Using Teflon tape and perhaps also silicone sealant, thread in the fittings you removed from the old pump. Note: Do Not Over-tighten, turn only 1 1/2 turns past hand tight. Using rubber mission couplings, PVC unions or simple slip x slip couplings, reconnect the pipe you cut. On PVC fittings, use a good primer and good, fresh PVC glue for pressure applications.


Wiring up a new pump motor...


First, screw in the conduit adapter onto the back of  the motor. This adapter is usually removed from the old pump and screwed into the 3/4" threaded hole where the wires enter the back of the motor. Some motors offer an additional port of entry on the top for wiring flexibility. Remove the back of the motor and run the wires in through the adapter, and tighten down the threaded connector to secure the wires and keep out moisture and insects. Notice where the wires enter the back of the motor, on the right side, a terminal board that has 2 brass screws for clamping down the 2 wires (lines) coming in. It doesn't matter which wire goes to which screw. Above the terminal board, there is a green screw that is for clamping down the ground wire.

All pump motors are wired to receive 230 Volts from the factory. That is, 2 lines (wires) carrying 115 Volts each. So, you need to know if you have 115 Volts coming in, or if it's 230 Volts. Usually 230 Volt service will have 2 wires of the same color, (and one green ground wire), while 115 Volt service will have perhaps one red (hot), one white (neutral), and one green. You should use a meter to be sure, but you could just look at the breaker. If 2 of the wires come off of one breaker, then you have 230 Volts. If one is connected to a breaker, and the other to the 'neutral' Buss bar, then it is 115 Volt service. Or look at the voltage plate on the old motor and see how it was hooked up. Is it matching the Low Voltage diagram (115 Volt), or matching the high voltage diagram (230 Volt)?

If you have 230 Volt service, hook up the wires coming into the motor to the brass terminals described above. If you have 115 Volt service, follow the instructions on the motor label to switch the motor to receive 115 Volt. This is a very easy switch of only one wire. Again, the motor comes factory wired for 230 Volt. If you are connecting 115 Volts to it, then switch the motor first. Putting 230 Volts into a 115 Volt motor can damage the windings, and perhaps fail the motor. After switching the motor to 115 Volts, connect the power wires to the brass terminals as described above (again it doesn't matter which wire goes to which screw).


Replacing the motor (not the plastic wet end, just the motor)


Having learned how to remove and break down a pump and motor in the previous sections, replacing any of the components is simply a matter of disassembling the pump down to the component that needs replacement, getting a replacement part, and reassembling the unit. Of course, if the entire pump and motor is to be replaced, you purchase the replacement as a unit and plumb it in as previously described.


Sometimes the motor will trip the circuit breaker when you try to start it. If this happens it is usually because there is something wrong with the motor; however, it could be a bad breaker or one that is simply undersized for the job and has finally worn out. To replace the motor here is the procedure:

  1. Break down the unit as described in the section on changing a seal. Remove the shaft extender by removing the Allen-Head setscrews and pulling the extender off the motor shaft. Sometimes this might need persuasion. Use your large flat-blade screwdriver to pry the extender away from the motor body. Sometimes corrosion will eat away at the setscrews and extender - if it is too tough to remove, replace it.

  2. Before sliding the shaft extender on the new motor, clean the motor shaft with a fine emery cloth such as you might have in your copper pipe solder kit. Apply a light coat of silicone lube to the shaft. When you put the extender on the motor shaft, the setscrews go into a groove that runs along the shaft. This groove allows the screws to grip and not slide around the shaft.

  3. Now slide the new extender in place, lining up the setscrews along the channel, but do not tighten the setscrews. When you have reassembled the bracket and seal plate, seal, and impeller, you can adjust the impeller to just barely clear the seal plate face, then tighten the setscrews. Be sure the impeller is screwed tightly onto the shaft extender before making this adjustment. If it is loose, when the motor starts it will tighten the impeller, by turning it tighter against the extender, thereby tightening it against the seal plate, seizing up the unit.

  4. Secure the shaft extender with your pliers or 3/8 - inch box wrench and lay a rag over the impeller. Firmly hand tighten it. Reassemble the remaining pump parts and/or re-plumb the entire unit back into place.

  5. Follow wiring instructions above, in previous section on installing new pumps.



I always try to stress to pool owners that a lot of air in the pump or loss of prime problems are due to lack of lubrication on the pump lid o-ring. Lubricants like Magic Lube (Teflon based) or Jack's Lube are always a great choice. Remember that a little dab will do the job. Never use a petroleum based product (i.e. Vaseline) for lubrication on o-rings. Inspect the pump o-ring for cracks, splits, or pinch marks. Finding little problems can prevent big problems from occurring.


Replacing the Mechanical Shaft Seal


All pumps have seals to prevent water from leaking out along the motor shaft. When these wear out due to overheating, vibration or a sudden change in water pressure - you will need to replace your pump shaft seal. The first thing to do is to turn off the electricity to the motor at the breaker.

  1. To access this seal for replacement, remove the four bolts that hold the pump halves together, it is not necessary to remove the entire pump from the plumbing system.

  2. Grasp the motor and pull it and the bracket away from the pump volute. Wiggle it slightly from side to side as you pull back to help break this joint.


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