Actual pump HP


Bronze Supporter
LifeTime Supporter
Jul 6, 2015
Charter Oak, California
Pool Size
Liquid Chlorine
Good Morning....This is from Hydraulics 101:

Pump Motor Nameplate

Most in the industry have long understood that pump motor nameplates can be very deceiving which often leads to incorrect sizing. It is bad enough that manufactures have chosen to have two classes of IG pumps, up rated vs full rated, but AG pumps also come in an "Special HP" (SPL) version which is basically a double up rated pump.

So what do all these terms mean?

The horsepower required to turn an impeller at a specific RPM is called brake HP (BHP). The required BHP changes along a pump's head curve and reaches a maximum near the right side of the curve. A motor will typically be rated at a service factor HP (SFHP) or total HP (THP) which is greater than the maximum BHP required for the pump. The SFHP/THP is the true measure of a motors power capability and is determined by multiplying the pump's service factor by the label HP. This is where a lot of the confusion originates. As a general rule of thumb, here is how a pump's service factor relate to the ratings.

To figure out the actual HP of this pump, do I multiply the stated HP of 2 by the SPL which is .25? Meaning that it's actually a .5HP pump??

Thanks in advance for the help.....


  • Pentair Pump.jpg
    Pentair Pump.jpg
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Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
Laughlin, NV
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
2 speed pump.
High speed is 2 hp
Low speed is 0.25 hp.

SF is 1. So not up-rated.
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