# Pump calculations

how to calculate the pump performance curve vales for Volume flow rate, RPM, Head pressure, pump power, impeller diameter for centrifugal pump. This can be applied to pumps within HVAC industry such as chilled water pumps.

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In this article we learn how to perform pump calculations in both imperial and metric units to assess pumping performance following the change of flow rate, pump speed, head pressure and power. These formulas are common practice rules of thumb and provide theoretical values to which actual values will likely differ. YouTube video tutorial at the bottom of the page.

To calculate the new flow rate of a pump from an increase or decrease in pump speed RPM, the following formula and calculation can be used.

To calculate the new flow rate of a pump from an increase or decrease in impeller diameter, the following formula and calculation can be used.

To calculate the new pump speed RPM from an increase or decrease in flow rate, the following formula and calculation can be used.

To calculate the new pump head pressure from an increase or decrease in pump speed RPM, the following formula and calculation can be used.

To calculate the new pump head pressure from an increase or decrease in flow rate, the following formula and calculation can be used.

To calculate the new pump head pressure from an increase or decrease in pump speed rpm, the following formula and calculation can be used.

To calculate the new pump impeller diameter to suit a change in pump flow rate, the following formula and calculation and be used.

1. sugiandhomo

how to avoid capitation at submersible vertical turbine pump,
how minimum level water from pump submersible to avoid capitation.

2. Faquruddin Ali Ahmed

How we can do pump head calculations in hvac any example

3. Saleemuddin

how can we calculate the rpm (2pole, 4 pole, 6 pole or 8 pole) for required Discharge and head

4. Hiii evans,

Can you please tell me the direct relationship between pump capacity, head, impeller speed and impeller dia.

Best regards,
AJAY K

5. Kevin

how can you calculate a pump requirement for a water pumping system in the following arrangement

flow rate of 17 L/min, viscosity of water , 38m of 1/2” ID piping with a 10m lift and also include joints and explain how you might calculate looses in those joints.

6. lemani kampango

i need to learn also. kindly show me

7. Morosi maposa

8. Steve

I am sorry, but the calculations for head pressure from increase/decrease flow rate, doesn’t really make sense, if your flow rate goes down, your head is supposed to go up… Unless I am missing anything here…

9. How can I get the Pump Calculations?

10. Nasar khan

Dear all
I need pump calculation sample way if i have 5 hp pump and use water for three floors so please clarify.
thanks all my friends

11. Sami Ullah

good