Things to Know That Can Damage Your Submersible Pump!
As the name suggests, a submersible pump, often called bore pump, sub pump or an electric submersible pump (ESP), is one that is submerged, usually in water or oil.
You are here probably to learn about things to know that can damage your submersible pump.
These submersible pumps are built to last for several years.
But as with all machines, things do go wrong either by incorrect usage or by natural causes and deterioration over an extended period.
However, if you’re knowledgeable about what are the things that can damage your submersible pump, you may prolong the lifespan of it by taking steps to prevent those things from happening.
So, without further ado, let’s begin. Shall we?
Reasons for Failure of Submersible Pump
There are mainly two types of causes for damage to a submersible pump.
1. Causes of Submersible Motor Burning/Coil Burn
One of the most common problems that affect the motor of a submersible pump is over-temperature. This can happen for numerous reasons including the motor overworking to pump hot water, scarcity of coolant fluid for the motor, debris or scale buildup inside the motor and frequent on/off or abrupt power outage, etc.
Deep submersible pumps naturally cool down as it is submerged in cool water and deep into the earth’s surface where the temperature is relatively cooler than that on the surface. However, these pumps work hard and they do generate substantial heat that gets transferred into the surrounding water and thus it cools down. But if part of the motor or pump is not submerged fully for some reason it may lead to overheating and as a result, the motor burning occurs which can lead to a serious hazard.
Mechanically, the way the submersible pump works is by using fluid film thrust bearings. Normally, the standard submersible pumps are water lubricated. A thin film of water acts as a lubricant between the two bearing surfaces. When the motor gets overheated for some reason, this thin water film can reach to its boiling temperature. When this happens, due to the non-existence of lubricant, the bearing surfaces come into contact and friction-heat generates rapidly. The result is disastrous – the bearings fail, meaning the whole pump system fails to work.
Hydraulic Loading/Water Hammer
If you’re a user of a submersible pump, you may or may not have heard the commonly used word “water hammer”. A more technical name for water hammer is hydraulic loading or hydraulic shock loading. Water hammer happens when a fast-moving column of water suddenly gets obstructed or the velocity changes abruptly. Commonly water hammer happens when multiple pumps are used on a common supply source.
The motor’s thrust bearing receives a sudden down thrust through the pump when water hammer happens.
This can cause serious damage to the motor.
The Motor Seal is responsible for preventing the well fluid from getting into the bag chamber and the thrust bearing section.
The primary function of a motor seal is to transfer the motor torque to the pump shaft.
It is a layer of sealing between the intake and the motor itself.
It protects the internal motor bearing by offering a sealing to keep abrasives and debris out of the motor bearing.
2. Additional Causes of Submersible Pump Failure
Submersible pump running backward
When the wiring is reversed or incorrect in the pump system, this can cause the motor to run backward. And as a result, insufficient water gets drawn by the pump and consequently it hamper the impeller, motor and the pump.
Often referred to as “Reverse Rotation” is a phenomenon that occurs when the pump is wired incorrectly and thus yielding the motor to run backward. This results in little to no water being pumped. This can cause serious damage to the submersible pump, polishing the impeller and eventually leading to cavitation*.
Submersible pump running dry
If the water level depletes a lot, the pump fails to draw a sufficient amount of water, then the pump is called to be “running dry” and this causes cavitation*, damages the impeller. Ultimately damaging the submersible pump. As the water level drops, the motor seal rubbers also dry out and start to disintegrate and have cracks, allowing water to get into the motor bearings.
Submersible pump drawing high current/amps
If your pump is drawing high amps or current (evident from electric bills), you should know that this is happening due to low voltage supply as the current is inversely proportional to voltage. As a result of low voltage, the pump draws excessive current to keep up with the torque of the motor. This could also happen from a short-circuited conductor.
Deadheading means that the pump is failing to discharge the fluid due to a closed valve. What happens when deadheading occurs is that the fluid starts to agitate inside the pump and vaporizes. The hot vapor causes the motor seals to have melted, dry out, and have cracks. Once the seal is broken or can’t offer protection anymore, the motor gets damaged ultimately. Often the result is as disastrous as breaking the motor shaft.
Cavitation – it is the development of bubbles around the impeller. As these bubbles form and burst, they generate a strong shockwave inside the fluid. It may seem not a big deal, but it is!
Because the sheer number of the bursting bubbles and constant pressure on the impeller and other pump gears causes erosion over time.
Things to know That Can Damage Your Submersible Pump Video
Knowing about things that can damage your precious and important submersible pump may save you from spending hundreds to thousands of dollars in repairing and a lot of headaches in the future. This may not be a comprehensive list of things that can damage your pump. However, these are the most common and fatal causes that if left unattended may lead to serious damage to your submersible pump.