Detaching a Pump Motor
People often refer to it as the 'pool pump' and that's fine, so long as there isn't a problem. It's when there is a problem that you realize there are two very different elements involved in this one piece of equipment: A Pump and A Motor.
Pumps rarely have problems, which is why the pump housing is joined confidently and permanently to the plumbing. The motor is the 'problem child' in this pairing and why it always separates and slides away from the pump for easy repair.
There are several misfortunes that can befall a motor and most are repairable, once you can figure out what the problem is.
The first diagnostic tool you use are your own good senses. A faint smell of ozone means a loose wiring connection under the access cap, often a simple repair. A quick sniff that has you tasting pennies can mean a bad capacitor, a simple replacement. A motor that's hot to the touch on one end or the other needs new front or rear bearings and a motor that makes a banging sound can have a bent shaft or debris in the cooling fin. But when you see smoke or sparks or hear a buzzing, hair raising Tesla Ion Coil (think Bride of Frankenstein), there's a short in the windings and that's an excellent reason to install a brand new motor.
For serious repairs, you detach the existing motor. When your pool was built, the orientation of the pool pump was decided by a plumber and the only consideration was easy access to valves and the strainer basket. Where the motor ended up was rarely given a passing thought. How tough can it be to detach a motor? Your competition can do it in under 10 minutes.
(photo top right) Most manufacturers use 4- 5/8" bolts to secure motors to pumps. The Sta-Rite-PacFab style pump and motors also feature a quick- split housing secured with a large steel band for easy field access to the impeller. Both style motors waterproof this connection with a rubber 'O' ring that should be replaced if it's been more than a few months since pump and motor were last separated.
The very first thing you do is shut off power to the pool sub panel or timer box. I'm at the maintenance engineers or homeowner's elbow when the breaker is shut off. And then I place duct tape over the breaker and a small lock (or screwdriver) to secure the access panel and I still use an ampmeter to check the timer box for power. Paranoid? You bet. Dance the 220 volt mambo once, and you'll be double checking the power line, too.
Trust me on this: It is just about always easier to detach the electric connections at the power source (timer box, junction box or on/off switch) and move the electric conduit and wiring (the 'whip') along with the motor than it is to deal with the electrical connections of an in-place residential pump motor.
Open the timer box and brush the plastic protective pane aside. There are three wires running from timer to motor; two from the switch panel deal with electricity, one is the ground connection. Loosen and pull the ends free. If any of the wire ends are bent, straighten them.
(photo, left) There is an electricians threaded fitting (generally a 90 degree elbow) where the conduit exits the timer and runs to the motor. A thin, metal ring holds this threaded fitting in place. Use a small flat screwdriver to tap the ring in a counter- clockwise direction. The elbow will pull free and tow the three wires with it. Also loosen any clamps anchoring conduit to the building wall.
Finally, open the ground lug on top of the motor and detach the green coated (or solid copper) ground wire. If the lug is morbidly corroded and will not open, you can snip the wire. The motor with electric whip attached is then ready to move to a more convenient work station.
If you are changing out the motor, you'll find the formed styrofoam packing that cradle shipped the new motor makes a sturdy vertical holder for the old motor (photo, right) .
Open the bell end cap on the power end of the motor. You'll find another electrician's metal securing ring on a threaded fitting and the terminal ends of your three power wires. Undo them all and pull the whip free of the motor. Examine the insulation at the wire ends. If the coating is cracked or chipping off, replace the wires or assemble a whole new whip in any hardware store for under $10 (US).
A plastic cover called the 'Volute' protects the impeller. Most volutes are held with tiny screws, some Hayward style volutes simply snap into place. Remove the volute.
You'll next see a 6" wheel that is the reason the motor spins. This is the impeller. Turn the impeller and locate the other end of the shaft at the front end of the motor. You may have to gently lift a spring- mounted governor weight to access the shaft.
(photo, right) There will be two flat sides on this shaft that a 1/2" open end wrench fits. The condenser has been moved aside. Carefully turn the impeller until the wrench slides over and holds the shaft in place. The impeller unscrews like the lid on a jar. Note that some impellers are held in place with a screw at the end of the shaft and a few older impellers even have an Allen set screw.
If there are still four bolts holding the pump housing to the motor (Sta-Rite type), remove them now. Wiggle the housing off the shaft and the shaft seal will come with it.
A rubber washer on the shaft behind the housing is the 'Slinger'. An under- appreciated safety feature, the slinger is what prevents any water that gets past a faulty shaft seal from getting to the electrified part of the motor. No one asks for a slinger anymore, so parts houses rarely carry them but you can make a functioning slinger out of the rubber cap that protects the threads on a new motor shaft. Simply cut a sliver ring from the cap and slide it on the shaft before you reseat the pump housing.
At this point, the motor is completely separated from the pump and electric service and is ready for repair or replacement.
Additional pool pump and motor repairs, routine maintenance and pump typing and sizing are further explained with color photos, drawings, graphs and simple text in the 690 page Pool School PRO CD
Excerpts from Pool School, pictures, text, graphics and web page design © 1997-2013, Scott Cruikshank, all rights reserved. Reproduction in whole or in part in any form or medium without express written permission of the author is prohibited.