Centrifugal Pump Troubleshooting: Pump Runs Hot

Another pump failure that we probably meet is the pump running hot or running at abnormal temperature than it should be. There are several potential causes that can lead to this.

1.Pump Running At Small Flow

If a pump is running at a small water flow, it may experience reduced efficiency and potentially overheating. This can occur when the system resistance is too large, or the valve opening is too small, or the pump simply runs low flow under power frequency.

Solution:

Check the reason of excessive system resistance and solve it.

Open the valve wide to let the water flows larger.

Use frequency conversion device to reduce operating frequency and speed.

2.Mechanical Friction

When the friction occurs in the rotating parts such as impeller and pump body, rotor and stator, or bearings, it increases the power consumption of the motor and it overheats.

At this situation, the motor surface is hot and there is noise of friction.

Solution:

Repair or replace the components for friction.

3.Low Voltage

When the motor is running at lower voltage than rated, the working current will exceed the rated current under full load which causes the motor temperature rise as well as the cable heat.

Solution:

Increase the power voltage to the rated power range.

4.Wrong Wiring(Three phase motor)

The three phase motor has mislead the star wiring to delta wiring.

Normally, there is wiring diagram at the terminal box for three phase motor. It is easy to check if the wiring is wrong.

Solution: If the wiring is wrong, correct it in time.

5.Insufficient Cooling

If the pump is not adequately cooled, it will overheat and cause an abnormal temperature rise. This problem may arise when the motor fan is being sheltered, the cooling fan is covered with dirts and debris, or the ambient temp. is too high.

Solution:

Adjust the installation to ensure sufficient air flow

Clean up the cooling fan.

Decrease the ambient temperature

6.Overloading:

If the pump handles more flow or pressure than it is designed for, it can cause the temperature to rise. This can be due to a blockage in the pump or system, or the valve opens too large.

Solution:

Adjust the valve opening gradually until the linear current is smaller than the rated one.

7.Pump Cycles (Pressure problem)

If the pump’s setting pressure is not suitable, it will get frequenct start and stop.

The pump stops quickly after it just started, and when the pressure drops to the start pressure, it will start again quickly. After cycles, the motor gets overheat.

Solution:

Adjust the value of stop pressure, ensure:

System pressure+ Pump Working Pressure＜Stop Pressure

System pressure+ Pump Max. Pressure＞Stop Pressure

8.Pump Cycles (System Leakage) 

When the system does not use water, the pressure drops after the water pump stops, and the water pump starts again. This is caused by system leakage when the pressure cannot be maintained after pump stops, and the pump starts after the pressure is lost.

Solution:

Check the leaks and fix it.

Adjust the frequency converter parameters to reduce the pump pressure, and delay the pump start interval.

It is important to identify and address the cause of an abnormal temperature rise in the pump and check it out before it gets larger damage and loss.