Why does a well pump run dry?

For homeowners who depend on well water, a well pump going dry can be a serious problem. Comprehending the causes of this issue is essential to preserving a consistent water supply and preventing possible harm to the pump itself. There isn’t any water in the well for the pump to draw when a well pump runs dry. If you don’t take immediate action, this can cause damage and overheating.

An obvious reason for a well pump to go dry is a decline in the water table. This may occur in times of drought or when the region experiences excessive water use. A dry run will result from the pump being unable to draw water if the water level drops below it. To avoid this situation, water levels and usage must be closely monitored.

A problem with the pump or the well system itself could also be the cause. The pump may run without enough water due to problems such as a damaged pressure switch, a burst pipe, or a malfunctioning check valve. The well system can benefit from routine maintenance and inspection to help identify and address these issues before they lead to the pump going dry.

In certain cases, the issue may arise from an incorrectly sized pump. The well may run dry if the pump is too big for it because it may draw water more quickly than it can refill. For the well to operate as efficiently as possible, the pump’s capacity must be properly matched.

Proactively addressing the problem of a well pump going dry requires knowledge of these possible causes. A dependable water supply can be maintained and the well pump can be shielded from harm with the help of routine well inspections, water level monitoring, and appropriate equipment sizing.

Why does dry running occur??

The most frequent cause of pump failure is dry running. Furthermore, because the owner permitted the equipment to be used improperly, the equipment in this instance cannot be fixed under warranty.

The following causes are most common when the pump enters "idle" mode:

1. Incorrect selection of the height of suspension of the water pump in a well or well shaft. This often happens when the depth of the source has not been calculated in advance. When the equipment pumps out the liquid medium to the level of its location, it begins to suck in air, causing the electric motor of the device to overheat.
2. The volume of water in the source has decreased due to natural reasons. For example, the bottom of the well has silted up or the liquid has not had time to accumulate in the well after recent pumping. Therefore, after pumping out the water, you need to wait a certain period for the source to fill again.
3. If a surface pump placed on a surface of water is used, the reason for its malfunction is often that the suction pipe loses its tightness and water is captured along with air, as a result of which the device’s engine is not cooled enough.

Because the pump lacks a sensor and a dry-running relay for protection, it overheats easily, burning out the electric motor and other components of the structure. Without enough lubrication and cooling, the pumping unit’s plastic components deform, reducing the device’s performance initially before causing it to overheat, self-jamm the shaft, and eventually cause the engine to fail.

There are various reasons why a well pump might run dry, but the most frequent one is a drop in the water table brought on by drawing water more quickly than it can be refilled. A damaged or clogged well screen, a decrease in aquifer water input, or mechanical problems like a broken pump or pressure switch are other contributing factors. To guarantee a steady and dependable water supply for your house or property, routine upkeep and observation can help avert these issues.

Types of dry running sensors

Pumping units that have undergone costly modifications already have built-in dry-running protection sensors. For instance, these devices are included in all Grundfos brand pumps and some models from Sterwin, Watt, Whirlwind, and Wilo manufacturers.

The submersible pump and sensors need to be connected separately when using low-cost devices. Let’s delve deeper into the different kinds of these gadgets and the concepts that underpin how they work.

Three types of dry running sensors exist:

• protection relay;
• level sensors;
• water flow and pressure sensors.

Protection relay

The device that regulates the water pressure passing through the pump unit is electromechanical. The power circuit opens as the pressure drops.

Three components make up the pump dry-running protection relay: a membrane, a contact group, and multiple cables. Fluid pressure is managed by the membrane. It is open and operational. The pump shuts off when the pressure falls to between 0.1 and 0.6 atmospheres because the membrane compresses the relay contacts. The following violations are indicated by a drop in pressure to this value:

• the fluid pressure has dropped to a minimum level due to the exhaustion of the source;
• pump filter clogged;
• the pump is above the water level, so the pressure has dropped to zero.

The protection relay may be surface-mounted as an independent component or integrated into the device body.

In the event that the water supply structure has a hydraulic accumulator, a pressure switch and protective mechanism are mounted in front of the accumulator.

Water level sensors

The purpose of this kind of apparatus is to determine the actual liquid level in a well or wells. It is possible to use two kinds of sensors:

1. Float switch. The connection diagram for the dry run analyzer must be assembled in such a way that its contacts are included in the power supply circuit of the pump motor. The float is floating. When the level of the working medium decreases, the float changes its position, its contacts open, and the pump turns off. This is the simplest method of protection, which is durable and easy to operate.

Counseling! You must properly configure the float in order for it to function promptly. It is crucial that the pump housing remains submerged in the liquid medium when the sensor is activated.

2. Sensor for water level. This relay is made up of two independent parts that have been lowered to various depths. One device has its pump operating level lowered to the lowest feasible setting. Slightly below is where the second sensor is situated. A tiny current flows between the two devices when they are submerged completely. The working medium level must drop to a minimum value in order for the current to stop flowing and the sensor to be activated, opening the power circuit.

3. Pumping equipment can be turned off before the device’s body is above the water’s surface thanks to sensors that keep an eye on the liquid level. This indicates that there is complete damage protection for the equipment.

Water flow and pressure sensors

The pump is equipped with two different kinds of water flow sensors that track the working fluid’s flow and make sure the pump doesn’t run dry. These are controllers and switches for flow.

1. The flow switch is an electromechanical type product. There are turbine and petal. The principle of their functioning also differs:

• the rotor of turbine relays contains an electromagnet that generates an electromagnetic field when fluid passes through the turbine. Specialized sensors read electrical impulses generated by the turbine. When the pulses disappear, the sensor turns off the pumping device from the electrical supply;
• there is a flexible plate in the petal devices. If water does not penetrate the pump, the plate moves away from its original location, causing the mechanical contacts of the relay to open. In this case, the power supply to the pumping device is interrupted. This option is characterized by simplicity of design and affordable price.

When there is no water flow, these block modules turn off the pump; when the system pressure falls below a predetermined threshold, the device is turned on.

2. Flow controllers (press control, automation unit). These are electronic devices that track multiple significant flow characteristics at once. They perform pressure checks, indicate the end of water suction, and switch on and off pumping equipment automatically. Check valves are found in many mechanisms. The high cost is justified by high reliability.

A well pump going dry is a frequent problem that, if left unattended, can cause serious harm. This issue typically occurs when the well’s water level falls too low, making it impossible for the pump to draw in water. This can be caused by a number of things, such as drought conditions, seasonal variations, and increased water consumption. Regularly checking the water level is essential to preventing the pump from becoming dry and guaranteeing a steady supply of water.

Equipment failure is a significant contributing factor to a dry-running well pump. There is a chance that parts like the foot valve, pressure switch, or check valve will break and stop the water flow. These problems can be avoided with routine maintenance and prompt replacement of worn-out components. Installing a low water cutoff switch can also safeguard the pump by turning it off automatically when the water level falls too low.

Finally, a well pump going dry can also be caused by an incorrect well depth or location. Particularly in dry spells, wells that are too shallow or positioned incorrectly may not be able to sufficiently access the aquifer. It is possible to make sure your well is positioned and built to the best possible quality by seeking professional advice during the planning and drilling phases. Proactively addressing these variables can help you avoid the inconvenience of a broken water system as well as save time and money.

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