MyPool, Swimming Pool Pumps Guide

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Swimming Pool Pumps

Pool Pumps

We offer a complete line of swimming pool pumps and parts, from all the major manufactures.   Sta-Rite, Hayward,  American Products, Purex, Pac Fab, Jacuzzi and others Whether its a single part or a complete pump we can supply your needs

Sizing Swimming Pool Pumps

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The pump consists of two principal parts: A motor and the wet end. The motor provides the power to move the components located in the wet end. The wet end consists of a trap, and impeller, which is responsible for moving the water.

The pump is probably the most important single piece of equipment in the circulation system. Selecting a pool pump is determined by a long list of factors. It is best to review this list even if you are replacing an existent pump with the same size. If you are tempted to increase the HP of the pump, you must read and understand this.

Total dynamic head (TDH) is the sum of the resistance experienced by water flowing through the pipes and filter system. Each elbow, foot of pipe, fittings and anything else that is in the circulation system increases the Total Dynamic Head. The TDH will affect the flow rate. For a new pool this is somewhat more easy to calculate, but for an existing pool, with piping below the ground it is much more difficult.

Typical Calculation:

1. Friction Loss (vacuum Side)

Common Head loss factors
Vacuum (at pump) -
       Assumes 2" suction pipe not to exceed 40 feet.
       Minimal fittings - One 2" valve and full rated pump.

Total Dynamic Head
Horsepower of Pump
Feet of water
4.5 - 5.5 feet of water
7.0 - 9.0 feet of water
10.0 - 12.5 feet of water
13.5 - 16 feet of water

   Let's use a 1 HP pump to perform a calculation, Reading the table above we have 9 feet of head.

2. Friction loss (pressure side): _____(clean filter pressure) PSIG x 2.31 feet of head / PSIG = feet of head (pressure side). Typically filter pressure should be 10-15 pounds

Using 10 feet of pressure we will have 23 feet of head on the pressure side.

3. The Total Dynamic Head: __9_(Vacuum)__ + _23(Pressure)_  =     ____32__

Practically speaking 30-40 feet of head is a good estimate to size a pump. which can be adjusted upward or downward depending on the circumstances.

Typical Pool Pump Performance Chart

Pump Size Pump Output (GPM) versus Total Resistance to Flow (feet of Head)
  20 feet 30 feet 40 feet 50 feet 60 feet 70 feet
1/2 55 45 29      
3/4 67 58 47 31    
1 85 76 65 50 27  
1-1/2 97 90 80 67 50 10
2 116 111 99 85 70 51

Pipe Flow Characteristics

Pipe characteristic (maximum Flow)
Pipe Size (PVC)
Pump Output (GPM) versus Total Resistance to Flow (feet of Head)
Suction Line (vacuum)
Return Line (pressure)
1-1/2 " 50 GPM 65 GPM
2 85 GPM 105 GPM