How Reduce the Pump Capacity

all possible methods.
There are too many, you will probably get more help if you ask a more specific question.
Here's a couple to get you started
Turn it off 4/5 of the time.
Restrict the output.
Split the output and return 4/5 of the flow back to the source.
Reduce the supply voltage or frequency depending on the type of motor.
Obtain a certificate stating categorically that the flow is 240L/min
Del

If it is a centrifugal pump, the normal method is to restrict the out put flow with a control valve. As pointed out there are other methods you should make yourself aware of.

Regards JD.

Speed controller on the motor if the motor is applicable.

A valve on the output to restrict flow many over load the motor. It would increase power consumption of the motor. Would need to incorporate some relief with it returning water to the suction side.

A valve on the output to restrict flow is unlikey to overload the motor. Most centrifs draw more power with rising flow (falling head).

That said, by throttling, power drawn will not fall in proportion to the reduced flow, so efficiency will be well down.

Cheers........Codey

GA Codey

Thanks klearzen

Tony gave the correct answer - whatever you do you will not be operating in the efficient range for the pump.

Buy a new pump that is sized right and save money (power) in the long run.

one solution is to install a smaller impeller

If the impeller is much smaller in diameter, or if the pump is run much slower, it may not develop enough pressure to overcome the static head in the piping system. But if the impeller is thinner (smaller passages) and about the same diameter as before, it would maintain the desired head at decreased flow and decreased power requirement. This will depend on impeller choices and trims available from the mfr.

A new suitably selected pump/motor is probably the best option.

I am very thankful to all of you for your valuable replies. Thanks to all.

I have one more suggestion.

Sell your existing high capacity pump & buy a small new pump with same money.

You must be having approx 45 kW motor to drive pump. New pump with lower flow rate may require only 7.5-10 kW. Without spending anything reduced monthly electricity bill will be a bonus.

Running big pump highly throttled will reduce its life. New pump will definetely have more life.