Why Is My Well Pump Short Cycling?

Reviewed by: James Layton
Updated on:
January 15, 2024

Well pump short cycling refers to a water pump, typically used in wells or other water systems, that rapidly turns on and off in quick succession without completing a full cycle. Instead of running for an extended period as intended, the pump starts, pumps a small amount of water, shuts off, then repeats the cycle shortly thereafter.

In this article, I will explore the various culprits behind well-pump short cycling, empowering you with the knowledge to identify and address the underlying factors that disrupt the smooth operation of your water supply.

What Causes Well Pump Short Cycling?

Short cycling can be caused by a variety of factors:

1. Pressure tank issues

Pressure tanks play a crucial role in well systems by maintaining steady pressure and supplying water on demand. However, when pressure tank issues arise, such as a faulty air bladder or a waterlogged tank, they can disrupt the delicate balance of the system, leading to well-pump short cycling.

A common problem occurs when the air bladder inside the water pressure tank becomes waterlogged, losing its ability to effectively separate air and water. As a result, the waterlogged pressure tank fails to regulate pressure adequately, causing the pump to turn on and off rapidly in quick succession. 

With an insufficient air cushion, the pump may only run for a short period before reaching the desired pressure and shutting off prematurely, triggering the short-cycling pattern.

Furthermore, pressure tanks that are undersized for the water system’s demand can also contribute to short cycling. When the pressure tank’s capacity is too small to handle the required water volume, the pump reaches the desired pressure quickly and shuts off before a substantial amount of water is utilized. 

As a result, the pump must turn on again shortly after to meet the ongoing demand, creating a cycle of rapid cycling. In this scenario, the pressure tank fails to provide an adequate buffer for the pump, forcing it to operate frequently to maintain the desired pressure level. 

It is crucial to ensure that the pressure tank is appropriately sized for the water system’s demand to prevent short cycling and ensure efficient operation of the well pump.

2. Pressure switch problems

The pressure switch (also called a pump-pressure control switch) in a well system plays a critical role in controlling when the pump turns on and off based on the pressure in the system. However, if the pressure switch malfunctions or experiences issues, it can disrupt the normal operation of the water pump, leading to short cycling. 

One common problem is a malfunctioning pressure switch that fails to accurately detect the pressure changes in the system. This can result in the switch turning the pump on and off rapidly, even when the pressure hasn’t reached the desired levels. Frequent cycling can strain the pump and disrupt the water flow, causing short cycling patterns.

Another pressure switch-related issue that can contribute to short cycling is incorrect pressure switch settings or adjustments. Pressure switches have adjustable settings to determine the pressure range for the pump to turn on and off. If these settings are improperly configured, such as being set too close together, the pump will cycle more frequently than necessary. 

For instance, if the switch is set to turn on at a high pressure and turn off at a low pressure, it can lead to rapid cycling as the pump quickly reaches the high pressure threshold and shuts off shortly after. Proper calibration and adjustment of the pressure-switch settings are essential to prevent short cycling and maintain optimal pump performance.

3. Plumbing system issues

The plumbing system in a well system is a critical component that ensures the proper flow and distribution of water. However, various plumbing system issues can disrupt the balance and cause a well pump to short cycle. 

One common cause is a leak in the plumbing system. Whether it’s a dripping faucet, a faulty check valve, or a compromised pipe connection, leaks can lead to a drop in system pressure. 

When the pressure drops below the threshold set by the pump-pressure control switch, it triggers the pump to turn on and restore the pressure. However, once the pressure is restored, the pump shuts off again, resulting in rapid cycling. Fixing any plumbing leaks is essential to maintaining proper pressure levels and preventing short cycling.

Improperly installed or malfunctioning check valves can also contribute to water-pump short cycling. Check valves are designed to allow water to flow in one direction while preventing backflow. If a check valve is not functioning correctly, such as being stuck open or not sealing properly, it can create a pressure imbalance in the system. 

The pump may need to turn on more frequently to compensate for the pressure loss caused by the faulty check valve. Similarly, incorrect check valve installation can cause similar issues, allowing water to flow back into the well or the pressure tank and triggering rapid cycling of the pump.

Improper sizing of water supply pipes can also contribute to water-pump short cycling. If the pipes are undersized for the water system’s demand, it can create excessive resistance and pressure drops, leading to frequent pump cycling. Likewise, malfunctioning fittings or valves can disrupt the flow of water and cause pressure irregularities, triggering short cycling of the pump.

4. Pump-related factors

Pump-related factors can significantly contribute to well-pump short cycling. One common issue is a clogged or obstructed intake screen or filter. If the intake screen or filter becomes clogged with debris, sediment, or other contaminants, it can restrict water flow into the pump. 

As a result, the pump may struggle to draw in an adequate amount of water, causing it to cycle rapidly in an attempt to meet the water demand. Regular maintenance and cleaning of the intake screen or filter are necessary to ensure unobstructed water flow and prevent short cycling caused by clogging.

Incorrect impeller size or damage can also lead to well-pump short cycling. The impeller is a critical component responsible for generating water flow and pressure within the pump. If the impeller is damaged or worn out, it may fail to generate the necessary pressure, causing the pump to cycle rapidly to compensate for the deficiency. 

Additionally, an incorrectly sized impeller that doesn’t match the system’s demand can result in inefficient pump operation. The pump may reach the desired pressure quickly and shut off prematurely, triggering short cycling.

5. Electrical and power-related issues

Electrical or power-related concerns can have a significant impact on the operation of a well pump, leading to short cycling. One common issue is inconsistent power supply or voltage fluctuations. 

If the power supply to the pump is unstable, such as experiencing frequent voltage drops or surges, it can disrupt the pump’s operation and cause short cycling. Inadequate or fluctuating power can result in the pump struggling to maintain the desired pressure, leading to rapid cycling as it turns on and off to compensate for the power variations.

Incorrect wiring or connections can also contribute to water-pump short cycling. Faulty or incorrect wiring can disrupt the electrical signals between the pump control switch, control circuitry, and pump motor. 

This can lead to erratic pump operation, such as turning on and off rapidly or failing to start at all. Loose or damaged connections can further exacerbate the problem, causing intermittent power supply to the pump.

Electrical issues with the pump motor or control circuitry can directly impact the pump’s performance and lead to short cycling. Malfunctioning components, such as a faulty motor or control relay, can cause the pump to operate inconsistently or fail to start reliably. 

For example, if the motor fails to generate the necessary power or experiences electrical faults, it can result in rapid cycling as the pump struggles to maintain the desired pressure.

6. Well-related factors

Well-related factors can have a significant impact on the operation of a well pump. If the water level in the well drops below the pump’s intake, the pump may struggle to draw in an adequate amount of water. As a result, it may cycle rapidly in an attempt to maintain the water supply. This can lead to short cycling as the pump turns on and off frequently to meet the water demand.

Another well-related factor that can contribute to short cycling is a damaged or obstructed well screen or casing. The well screen or casing allows water to enter the well while preventing the entry of debris and sediment. If the well screen or casing is damaged, corroded, or clogged, it can restrict water flow into the well. This can cause the pump to cycle rapidly as it struggles to draw in water through the obstructed screen or casing.

The presence of too much air in the well system, often referred to as air entrainment, can also contribute to well-pump short cycling. Air can enter the well system through various sources, such as a faulty check valve, a compromised well seal, or a leak in the system. When too much air is present in the well, the pump may experience difficulty generating and maintaining pressure, leading to rapid cycling as it struggles to compensate for the presence of air.

7. Insufficient air charge in the water tank

The air charge in the water tank acts as a buffer or cushion to regulate the water pressure in the system. When the well pump turns on, it draws water from the tank, compressing the air inside. As the air pressure decreases, the water pressure increases. 

Conversely, when the pump turns off, the compressed air expands, pushing the water out of the tank and maintaining a steady pressure. However, if there is an insufficient air charge in the tank, the pressure regulation becomes compromised. As a result, the pump may rapidly reach the desired pressure and shut off prematurely, causing short cycling.

Without an adequate air cushion, the water pressure in the tank can fluctuate more rapidly. When the pump turns on, it quickly builds pressure, but due to the lack of a sufficient air charge, the pressure drops rapidly as the water is drawn from the tank. 

This rapid pressure drop can trigger the pump to turn on again, repeating the cycle in quick succession. The constant on-off cycling not only strains the pump but also affects the overall performance and efficiency of the well system.

Short cycling due to insufficient air charge puts excessive stress on the water pump. The frequent starting and stopping can lead to increased wear and tear on the pump motor, impellers, and other internal components.

Over time, this can result in decreased pump lifespan, decreased water flow, and potential pump failure. Additionally, the rapid cycling can disrupt the water supply, causing fluctuations in water pressure and affecting the functionality of plumbing fixtures and appliances connected to the system.

8. Water filter issues

Some water filter systems, especially those that use fine filters or membranes, can create a significant flow restriction in the water supply line. If the filtration system is installed without considering the flow requirements of the well pump, it can lead to increased resistance and pressure drops in the system. This can result in the pump struggling to maintain the desired water pressure and potentially lead to short cycling.

A water filter system can introduce a pressure drop in the water supply line, particularly if it includes multiple filtration stages or high-efficiency filters. A significant pressure drop can affect the overall system pressure, triggering the well pump to cycle more frequently to compensate for the pressure loss. While this is not a direct cause of short cycling, it can indirectly contribute to increased water pump cycles.

Different Well-Water Pump Systems and Short Cycling

Various types of well pumps can experience short cycling if certain conditions or factors are present. However, certain pump types may be more prone to short cycling than others due to their design or functionality. The following types of well pumps are commonly associated with short cycling:

Jet pumps

Jet pumps are known for their susceptibility to short cycling. They consist of a motorized pump that is located above ground and a jet assembly that is submerged in the well. Jet pumps can experience short cycling if there is a problem with the jet assembly, such as a malfunctioning venturi valve or a clogged nozzle, causing the pump to cycle rapidly.

Shallow well pumps

Shallow well pumps are designed specifically for wells with a depth of 25 feet or less. They are typically non-submersible pumps and are more prone to short cycling due to their limited capacity and lower pressure ratings. If the demand for water exceeds the pump’s capabilities, it may cycle frequently to maintain the desired pressure.

Constant pressure systems

Constant pressure systems, such as variable frequency drives (VFDs) or constant pressure controllers, maintain a steady water pressure regardless of demand. While these systems provide convenience and consistent pressure, they can be more susceptible to short cycling if there are issues with the pressure sensors or control mechanisms. Improper settings or faulty components can cause the pump to cycle rapidly in an attempt to maintain the desired pressure.

Overpowered pumps

If a well pump is oversized for the water system’s demand, it can lead to short cycling. Overpowered pumps reach the desired pressure quickly and shut off before enough water is used, causing frequent cycling. This can occur with various types of pumps, including submersible pumps, centrifugal pumps, or turbine pumps.

How to Prevent Well-Pump Short Cycling

If your well water pump has frequent episodes of short cycles, here’s a list of measures you can take to prevent these situations:

  • Proper pressure tank sizing: Ensure that the pressure tank is appropriately sized for your water system’s demand. A well-sized tank provides sufficient water storage capacity, reducing the frequency of pump cycling and preventing short cycling.
  • Regular air charge maintenance: Monitor and maintain the air charge in the pressure tank. Recharge the tank with air as needed to maintain the recommended air pressure level. This helps ensure proper pressure regulation and prevents short cycling.
  • Adequate pipe sizing and design: Ensure that the pipes in your system are properly sized and designed to minimize resistance and pressure drops. Correct pipe sizing, layout, and the use of appropriate fittings help maintain optimal water flow and reduce the likelihood of short cycling.
  • Well system maintenance: Regularly inspect and maintain your well system components. This includes cleaning or replacing clogged intake screens or filters, inspecting the well screen or casing for damage or obstructions, and addressing any air entrainment issues promptly.
  • Electrical system stability: Ensure a stable and consistent power supply to the well pump. Address any electrical issues, such as voltage fluctuations or wiring problems, promptly to prevent disruptions in pump operation and potential short cycling.
  • Professional installation and maintenance: When installing or repairing your well pump system, enlist the expertise of a professional water pump technician or plumber. They can ensure proper installation, adherence to industry standards, and regular maintenance to minimize the risk of short cycling.
  • Well pump location and placement: Properly position the well pump, ensuring it is placed at an appropriate distance from the water surface to avoid air entrainment and in a location where it can draw water efficiently.
  • Regular monitoring: Continuously monitor the performance of your well-pump system, including water pressure levels, cycling frequency, and any unusual patterns. Promptly address any deviations or issues to prevent further complications and potential short cycling.

Conclusion

Short cycling can occur due to various factors. Understanding why your well-water pump is short cycling is crucial to resolving the issue and ensuring the efficient operation of your water system. By identifying the root cause, you can take appropriate measures to address the problem and prevent further damage to your well pump.

Remember, when dealing with well-pump issues, it is always advisable to consult with a professional well pump technician or plumber who can provide expertise and guidance tailored to your specific situation. They can diagnose the problem accurately, offer effective solutions, and ensure the longevity and reliability of your well-pump system.

By taking proactive measures and seeking professional assistance, you can overcome well-pump short cycling, ensuring a consistent water supply, optimal performance, and peace of mind for your household.

If you want to know more about well water pumps, check out our guides and reviews below.

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