Creech Pump Index

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A BETTER WAY TO COMPARE POND PUMPS

The Creech Pump Index (CPI) is a way to compare the efficiencies, and operating costs, of different pumps. It is calculated by multiplying the pump head times the gallons per minute (at that pump head), and dividing by the watts consumed. Watts are calculated by multiplying the amps times the voltage.

CPI = Ph x GPM / Watts

The higher the Creech Pump Index (CPI) the lower the operating costs.

We need this yardstick to show just how much more efficient the Best Pond Pumps® are compared to other pumps. They vary from 2+ to 3+; the + being the result of the reserve power. Other pumps are typically 1-2.

The CPI is simple Physics. It compares the work done by a pump i.e., the flow against the pump head, versus the power used to do the work.  It is simple to calculate, the more rigorous calculation is as follows:

Creech Pump Index = {GPM x Pump head x Specific Gravity x %Pump Efficiency} / {Watts}

Where GPM is gallons per minute, pump head (Ph) is the value for the given GPM, specific gravity is the density of the liquid (for water it is essentially =1). The %Efficiency is not usually given by the pump manufacturers, and usually is 60% or much less, but since we don’t know it, it is easiest to ignore it and just use 100% or 1, but please note as the pump %Efficiency goes down, so does the CPI.

If you knew the %Efficiency at any one point, you could calculate it at all points. You would divide the CPI by it to get the Maximum CPI (MCPI), and then divide all the other points by the Maximum CPI to get the %Efficiency.

The Creech Pump Index (CPI) is similar to the WATER HORSEPOWER:

Water Horsepower = {(GPM x Pump head)/ 3,956}

Brake Horsepower = Water Horsepower / % Pump Efficiency

Electrical Horsepower = Brake Horsepower / % Motor Efficiency

Unfortunately some manufacturers list their pumps’ amperage (amps), while others list the watts. Some pond owners do not know how to convert from one to the other. The correct conversions are as follows:

Amps x Voltage  = Watts or     Watts / Voltage = Amps**

Often the GPM (or GPH) is given at different pump heads. Now we can calculate the CPI for any pump. For example, let’s look at some of the publicly advertised pumps:

For instance, the Jacuzzi 2-speed SLR pumps are listed as follows:

  • 1 HP = 8.8 amps at 115 volts - the performance curves give 65 GPM at 27.5’ Ph

  • 1.5 HP = 12.2 amps at 115 volts - the performance curves give 73.5 GPM at 35’ Ph

  • 2 HP = 16.4 amps at 115 volts – the performance curves give 78 GPM at 43’ Ph

The CPI is 1.8 for all 3 of these Jacuzzi pumps.

The Sequence 2 HP K661.111 lists the amps as 25; with 2100 GPH @ 82’ Ph; 4200 GPH at 74 Ph; 6300 at 62 Ph; and 8160 at 43’ Ph. The Creech Index computes as 1.0; 1.8; 2.3; and 2.0. It is not the same because the % Efficiency at 43’ Ph is twice the efficiency at 82’ Ph; and with its most efficient performance at 62’ Ph. This is important information to know because we probably would not want to use a pump at a low efficiency point. However, if we average the CPI's for the Sequence 2 HP K661.111 it is 1.8, the same as the Jacuzzi pumps.

The Superfalls 1/10 HP pump KJ7000LH has a CPI of 0.2. The 5/8 HP Little Giant 4,100 GPH pump has a CPI of 0.8. 

The 1 HP Money Saver Pump® has a CPI of 3 or more for all HP’s including 3/4, 1/2, 1/4, 1/6, 1/8, & 1/10.

So the Creech Pump Index allows us to compare pumps and their energy efficiency, quickly and easily!  

Using the Creech pump index you can at last easily compare pumps!

  • Especially when 1 pump might use 115 volts, another 230 volts, and still another 460 volts.
  • Often one manufacturer will list energy requirements as amps, and another watts.
    • Remember:    amps x voltage = watts**
  • One manufacturer will list flow as GPM (gallons per minute), and another as GPH (gallons per hour)
    • Remember:    GPM x 60 = GPH
  • One manufacturer will list flow at 1 foot of pump head, another at 30 feet of pump head.
    • Remember: You must use the pump head for the GPM you are using.

We have shown the Creech pump index allows all these factors to be taken into consideration. The resulting CPI is a measure of the energy efficiency of each pump. The larger the number the more energy efficient is the pump. These numbers run from 0.2 to 3.1 with the 3.1 CPI being 15 times more energy efficient than the 0.2 CPI.

Try calculating the CPI for your pump!

Here is a list of Creech Pump Indexes for some of the more popular pumps:

Horsepower

Pump Name

 Creech Pump Index
1/15 Money Saver Pump (0-0.16 amps)* 3.0
1/15 Wave Pump WP-3000 (1.3 amps) 1.1
1/15 Aqua Flow (1.2 amps) 1.1
1/10 Money Saver Pump (0-0.26 amps)* 3.0
1/10 Superfalls KJ7000LH (4.0 amps) 0.2
1/8 Money Saver Pump (0-0.33 amps)* 3.0
1/8 Sequence 1000 K4H3,K5Th3 (1.7 amps) 1.8
1/8 Aqua Flow (1.7 amps) 1.6
1/8 Wave Pump WP-3800 (1.7 amps) 1.5
1/8 Sequence 750 J2H3, J5H3, J8H3 (1 amp) 0.9
1/6 Money Saver Pump (0-0.43 amps)* 3.0
1/6 Sequence 1000 K5J3.111 (2.2 amps) 2.2
1/6 Aqua Flow (2.0 amps) 1.7
1/6 Wave Pump WP-4100 (2.0 amps) 1.7
1/6 Sequence 500 F2SA1 (2.8 amps) 0.7
1/4 Money Saver Pump (0-0.65 amps)* 3.1
1/4 Power Plus Pump (1.25 amps)* 2.9+
1/4 Dragon Pump (2.8 amps) 1.9
1/4 Wave Pump WP-4980 (2.5 amps) 2.9
1/4 Aqua Flow (2.5 amps) 2.7
1/4 Sequence 1000 K7K3 (3.0 amps) 2.3
1/3 Money Saver Pump (0.87 amps)* 3.1
1/3 Power Plus Pump (1.6 amps)* 2.3+
1/3 Dragon Pump (3.8 amps) 1.8
1/3 Sequence 1000 K111.111 (8.7 amps) 0.5
1/2 Money Saver Pump (1.3 amps)* 3.1
1/2 Power Plus Pump (2.3 amps)* 2.2+
1/2 Sequence 1000 K221.111 (8.8 amps) 1.1
5/8 Money Saver Pump (0-1.6 amps)* 3.1
5/8 Little Giant 4100 GPH (7.1 amps) 0.8
3/4 Money Saver Pump (0-2.0 amps)* 3.0
3/4 Power Plus Pump (3.1 amps)* 2.0+
3/4 Dragon Pump (6.2 amps) 1.9
3/4 Sequence 1000 K331.111 (12 amps) 1.4
1 Money Saver Pump (0-2.6 amps)* 3.0
1 Power Plus Pump (4.25 amps)* 3.0+
1 Jacuzzi SLR (9 amps) 1.8
1 Sequence 1000 K441.111 (17 amps) 1.5
1 Little Giant 16EH-CIM (19 amps) 0.9
1.5 Money Saver Pump (0-4 amps)* 2.4
1.5 Jacuzzi SLR (12 amps) 1.8
1.5 Sequence 1000 K551.111 (19 amps) 1.8
2 Money Saver Pump (0-5 amps)* 2.4
2 Power Plus Pump (8.8 amps)* 2.7+
2 Jacuzzi SLR (16 amps) 1.8
2 Jacuzzi Magnum Force 2MF-S2 (22 amps) 2.3
2 Sequence 1000 K661.111 (25 amps) 1.8
2 Little Giant 20 GH (35 amps) 0.7
3 Power Plus Pump (11.8 amps)* 2.7+

* amps shown for 230 volts

**Actually to be rigorously correct for AC current we need to insert the power factor into these equations as follows:

Amps x Voltage x Power factor = Watts or Watts / Voltage = Amps x Power factor

The power factor is the cosine ø, where ø is the phase angle between the voltage and the amps, or ø is the angle between the vectors of Real Power and Apparent Power, and the vector opposite is the Reactive Power. Generally ø is = 0, and the cosine ø = 1, except for inductive and capacitive components.

This is especially important if one measures the amps, and then the voltage, in the field. For an inductive motor these will need to be corrected by the power factor. Unfortunately, the equipment needed to measure ø or the power factor, such as an oscilloscope, costs several thousand dollars. Fortunately, many motors list their power factor on the nameplate.

 

 

 

 

 

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