DO YOU NEED A PORSCHE OR A PICKUP

When it comes to replacing a pump you need to know what your conditions are to avoid problems later.  Let’s examine the performance characteristics of 2 Bell & Gossett PL series pumps, the PL-55 and the PL130. Initially many would assume that the PL-130 is a bigger pump and will flow at a higher rate than the PL-55, However that isn’t always true. 

Going back to the Porsche vs. Pickup analogy the Porsche can certainly outrun the Pickup any day of the week right, now hook a 7,000 lb trailer to the back of them and the Porsche doesn’t move and the Pickup runs away.  In this example the PL-130 is the Porsche and the PL-55 is the pickup.  Take a look at the pump curve below:

On the left is the feet of head the pump can operate against and along the bottom is the gallons per minute it will flow.  So at 10 feet of head pressure the PL-130 flows 85GPM while the PL-55 flows 45GPM, but increase the head pressure to 18 feet and the PL-130 drops to 25GPM while the PL-55 now is flowing 40GPM.  Next time your sizing a pump take a minute to consider the conditions it save time and money later on.