If you’ve ever seen a pump explode, then you are probably aware that it’s extremely destructive, expensive and even catastrophic. Ensuring that your centrifugal pumps do not overheat is not only crucial for efficient pump operation but is also critical for the safety of the pump operator and the plant.
An overheating pump can:
Cause damage to the surrounding piping and critical pump components
Shorten the pump’s life
And can even prove fatal for the pump operator and the plant
You can avoid the hassles of replacing a damaged pump and minimize pump replacement and repair costs by knowing the warning signs of overheating. Here are the top 5 signs to look for in an overheated pump.
Sign #1: It’s Too Hot to Touch
If the pump operator is able to bear the heat while touching the external parts of the pump, then the pump is working normally.
On the other hand, if the pump is too hot to touch or you can spot steam coming out from the pump, then you can quickly know that it’s overheating.
*Note that you should apply the heat touch only to the pump and not the motor. This is because electric motors are generally hot to touch even when they are running as intended. They heat up to 40-degree-Celsius, which is quite hot to touch.
Sign #2: You can hear Noises like Tumbling Rocks coming from inside the Pump
If you notice excessive sound coming from the pump, like tumbling pebbles inside it, then it’s a sure sign of cavitation. Pump cavitation can occur due to any of the following reasons:
Partial blockage on the suction line
Too high suction lift
High temperature liquids
Cavitation can cause severe damage to the pump’s impeller, causing it to overheat.
Sign #3: It’s Losing Prime
The internal parts of a pump stay cool as the fluid flows past them. If the pump loses prime, the water inside the casing can get very hot. This is because of the friction caused by the impeller. This causes the water inside to evaporate into steam.
When this happens, the steam inside the pump casing can cause damage to the impeller, pump seals and the plastic piping connected to the various parts of the pump. The main reasons why a pump loses its prime are due to:
A leaking shaft seal
Small air leaks in the suction line
So, It is necessary to keep an eye over it.
Sign #4: Clogged Pipe Lines
Clogs in the strainer or a suction line may restrict water flow leading to cavitation or loss of prime. Either of these issues can cause the pump to overheat.
Sign #5: The Motor is pulling in Excessive Current
The nameplate that comes along with your pump motor has vital information. Two critical pieces of information found on the motor include:
Full loan amps (FLA)
Motor service factor (SF)
The ampere is the unit of electrical current. It shows how hard the motor is working. At a specific voltage, the higher the amp, more work the motor is putting in. The FLA mentioned on the motor nameplate indicates the amount of current that the motor should draw when it operates at full loan. If the current drawn by the motor is significantly higher than the FLA, then it indicates a problem with the motor or pump.
Here are a few reasons why the pump may be drawing too much current:
Mechanical troubles like bad bearings
Pump operating at the extreme right side of the pump curve
Bad winding in the motor