Swimming Pool Blog
by Rob Cox, June 19, 2010
Pool Pumps: Rebuild or Replace?
Most pumps, with the exception of the Jacuzzi Magnum pump shown at left, have a ready supply of replacement parts available. You should have no problem rebuilding your own pool pump, if it needs a new impeller or diffuser or other internal parts. All gaskets and o-rings and seals - are available individually or in blister paks called Go-Kits .
Pump Parts don't usually come with instructions, but you can find on our website a lot of information on the Pumps & Motors Info page about how to troubleshoot a pool pump. If your pump has low flow, low filter pressure or air problems, you may not need any parts at all, but look to remove air leaks or obstructions before the pump impeller. Obstructions after the impeller, like a dirty filter or partially closed valve would cause high pressure and cavitation.
You'll find just about every pump out there on schematic diagram in our pool pump parts section of the website. More pump parts are scheduled to be added soon, including Astral, Speck and Waterway pool pump parts. If you've never seen our exploded schematic pool pump diagrams, you are missing out on one of the best parts of poolcenter.com. Most items install fairly simply, and it's rare that the cost of the parts would be more than replacing the pump.
Or maybe you just need a new pool motor, and not the entire pump? Pool pump motors are built with bearings, front and rear. Spinning at 3450rpm, they eventually wear out. Fortunately, they make you very aware of their demise by a screeching noise that gets louder as the bearings fail. Sometimes it takes a neighbor to point this out, but fear not, there is an easy remedy to a noisy pool pump motor.
2. A local electric motor shop would replace bearings and shaft seal for around $100.
3. You could replace the motor with new.
The last option has the benefit of everything being new, not just the bearings and shaft seal typically replaced during a rebuild. New windings, switches, capacitor, terminals, etc. Most pool pump motors last around 8 years, so a 2-3 year old motor may be a good candidate for rebuild, whereas a 6 year old motor may not be. Always replace the shaft seal when removing a motor (+/- $10).
When Should you Replace the Entire Pool Pump?
1. When you are required to by new laws mandating a Energy Efficient pool pump.
2. To lower your electrical costs by installing a Two Speed or Variable Speed pool pump.
3. When parts for your model pool pump are no longer available or hard to source.
4. When parts for repair of your pool pump are more than the cost of a new pump.
How Do I Select a new Pool Pump?
The best match would be to replace with the same make and model pump you have now, unless you found it's flowrate to be severely lacking. When your pool was originally designed, we can assume that the designer did the math, adding up all of the flow resistance, measured in feet of head, and selected a pump and filter based on these computations. The plumbing portion of pump installation will usually be easier if you replace like with like, as the height and setback of the in and out ports of the pump will line up with your existing plumbing configuration.
If however, your old pump is no longer made, or not made in an energy efficient model, or the entire pump and filter system is being renovated, you can switch pump models or manufacturers without a problem. Most important in changing pump models is to use the charts to get as close as possible to the flow rate and pipe height and setback measurements of your existing pump.
Remember to match hp and pump type and flow rate. Use the Flow Rate Charts, (see sample chart below) based on a average feet of head (vertical axis) of 20 feet. This is the only true way to compare pump to pump flowrates. Since you probably don't know the exact amount of resistance in your system, measured in feet of head, use an average amount, say 20 ft, when comparing your existing pumps flow capacity to a different make and model pool pump.
For Americans, it's only natural to want the big V8 power plant, but a pump that is too powerful could actually prevent filtration while damaging the filter and heater. Pipes or plumbing fittings could even be blown apart. When matching pumps to filters, check the Design Flow Rate of the filter from the filter label. The average flow rate for the pump you select, should be within 10% of the filter's Design Flow Rate.
Remember also, that a smaller hp motor is going to draw fewer amps, which is going to cost less to operate. If you are careful to match up flow charts, you could actually reduce the hp required, while increasing the head of the pump. For instance, a 3/4 hp Whisperflo produces the same amount of flow as a 1 1/2 hp SuperPump. So, you could replace one with the other, while electrical costs are nearly cut in half!
Next post we'll dive into motor replacement and new pool pump installation.
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So, when selecting a pump, keep it close to the original specifications, and use the Flow Charts. Most systems could handle a small increase in pump size, especially if you are replacing the filter with a larger one, but be careful not to install a pump that is too large for the pipes or other equipment.