AIM Manual

Motor Application » Pumptec Products (Page 8)

Hot Water Applications (Continued)

2. Determine pump horsepower required from the pump manufacturer’s curve.

Fig. 2: Manufacture's Pump Curve

3. Multiply the pump horsepower required by the heat factor multiplier from table 8.

Table 8 Heat Factor Multiplier at 3 ft/s (.91 m/sec) Flow Rate
Maximum
Water Temperature
1/3 - 5 hp
.25 - 3.7 kW
7 1/2 - 30 hp
5.5 - 22 kW
Over 30 hp
Over 22 kW
140 °F (60 °C)1.251.622
131 °F (55 °C)1.111.321.62
122 °F (50 °C)11.141.32
113 °F (45 °C)111.14
104 °F (40 °C)111

4. Select a rated hp motor on table 8A whose Service Factor Horsepower is at least the value calculated in Item 3.

Table 8A Service Factor Horsepower
hpkWSFhphpkWSFhphpkWSFhphpkWSFhp
416420.250.5832.23.452518.528.7510075115
416410.370.853.75.75302234.512593143.75
417020.551.127.55.58.62403046150110172.5
10.751.4107.511.5503757.5175130201.25
1.51.11.95151117.25604569200150230
21.52.5201523755586.25

Hot Water Applications - Example

Example: A 6" pump end requiring 39 hp input will pump 124 °F water in an 8" well at a delivery rate of 140 gpm. From Table 7A, a 6" flow sleeve will be required to increase the flow rate to at least 3 ft/s.

Using Table 8, the 1.62 heat factor multiplier is selected because the hp required is over 30 hp and water temperature is above 122 °F. Multiply 39 hp x 1.62 (multiplier), which equals 63.2 hp. This is the minimum rated service factor horsepower usable at 39 hp in 124 °F. Using Table 8A, select a motor with a rated service factor horsepower above 63.2 hp. A 60 hp motor has a service factor horsepower of 69, so a 60 hp motor may be used.