Pump Selection Questions

[psugreen]

2 questions in relation to pump selection:

1. For inline pumps should suction and discharge connections be line size, or is it ok for the pump to have a smaller connection than the pipes it connects too?

2. What is the best speed (rpm) to select pumps at?

 

[quark]

You can have smaller pump connection. Just use reducers properly, to avoid air pockets.

Nothing like the best speed. High speed pumps are smaller in size but life is shorter.

 

[KiwiMace]

I usually try to select a pump with a four pole motor; 1500 or 1800 rpm.

 

[Joesteam]

Most pumps have a smaller outlet size than inlet, and both are usually smaller than the piping. As for speed, 1800 rpm seems to be a standard in most HVAC applications, however if you have high head and low flow, the 3600 rpm option will give a much more economical pump and also more efficient. Also, most condensate and booster pumps buck the trend and are 3600 rpm. Finally, some engineers specify 1150 rpm motors as they are assumed to provide a quieter system

Joe Lambert

http://www.control-associates.com/

 

[willard3]

Higher rpm pumps make more noise.

Pump inlet and outlet sizes are almost always smaller than the pipe in which it's mounted for a lot of reasons.