Shallow Well Pump Short Cycling: A Comprehensive Troubleshooting Guide

Shallow well pump short cycling is a common issue that can be caused by various factors, including a loss of air charge in the pressure tank, a faulty or clogged water pump pressure control switch, blocked water supply piping, overcharging of the pressure tank, and leaks in the system. Understanding the technical specifications of your shallow well pump and the factors that can affect its performance is crucial to diagnosing and fixing the problem.

Shallow Well Pump Technical Specifications

The technical specifications of a shallow well pump include the following:

  • Motor Size: The motor size of a shallow well pump typically ranges from 1/2 to 1 horsepower (HP), with 3/4 HP being a common size.
  • Voltage: Shallow well pumps are usually powered by either 115V or 230V single-phase electricity.
  • Horsepower: The horsepower of a shallow well pump determines the amount of water it can deliver. A 1/2 HP pump can typically deliver 5-10 gallons per minute (GPM), while a 1 HP pump can deliver 10-15 GPM.
  • Flow Rate: The flow rate of a shallow well pump is measured in gallons per minute (GPM) and is influenced by the depth of the well, the size of the pump, and the water demand.

Causes of Shallow Well Pump Short Cycling

shallow well pump short cycling

1. Loss of Air Charge in the Pressure Tank

The most common cause of shallow well pump short cycling is a loss of air charge in the pressure tank. This occurs when the air pressure in the tank is not sufficient to maintain the water pressure, causing the pump to turn on and off frequently.

The ideal air pressure in the tank should be 2-3 psi below the pump cut-on pressure. For example, if the pump cut-on pressure is 30 psi, the ideal air pressure in the tank should be 27-28 psi. To restore the normal function, you can add air to the tank using a bicycle pump and drain some water to create room for the air.

2. Faulty or Clogged Water Pump Pressure Control Switch

Another common cause of short cycling is a faulty or clogged water pump pressure control switch. This can occur when the water is full of silt or other debris or when the water has high mineral content. Replacing or repairing the switch can restore normal function.

The pressure control switch is responsible for turning the pump on and off based on the water pressure in the system. If the switch is not functioning properly or is clogged with debris, it can cause the pump to short cycle.

3. Blocked Water Supply Piping

Blocked water supply piping can also cause the pump to short cycle. A clog in the water supply creates high water pressure very quickly, causing the pump to turn on and off rapidly. Checking the water filter and replacing it if it’s dirty or blocked can restore function.

The water supply piping should be free of any obstructions or blockages to ensure smooth water flow and prevent short cycling.

4. Overcharging of the Pressure Tank

Too much air in the pressure tank, known as overcharging, can also cause short cycling. This can occur in captive air water tanks, which don’t have a process for leaking excess air. Overcharging can damage the water tank or break the bladder, so it’s essential to avoid it.

If you think you’ve overcharged the system, turn it off, let out the water, and reset the air charge to the factory-specified pressure. The recommended air pressure in the tank should be 2-3 psi below the pump cut-on pressure.

5. Leaks in the System

In some cases, the problem may be outside the house and underground, such as a leaking foot valve. This can cause the pump to short cycle as water drains back into the well.

Leaks in the system can cause the pump to work harder than necessary, leading to short cycling. It’s important to check for any leaks in the piping, fittings, or other components of the system and address them promptly.

6. Check Valve Issues

The check valve is responsible for preventing water from flowing back into the well when the pump is not running. If the check valve is faulty or stuck open, it can cause the pump to short cycle as water drains back into the well.

Checking the condition of the check valve and replacing it if necessary can help resolve the short cycling issue.

Diagnosing and Fixing Shallow Well Pump Short Cycling

To diagnose and fix the problem, you can follow these steps:

  1. Check the air pressure in the tank and add air if necessary.
  2. Check the water pump pressure control switch and replace or repair it if necessary.
  3. Check the water supply piping and filter and replace them if necessary.
  4. Check the air charge in the pressure tank and reset it if necessary.
  5. Check for leaks in the system and fix them if necessary.
  6. Check the check valve and replace it if necessary.

If you’re noticing short cycling and can’t get to the problem quickly, it may be time to call a professional for help. They can quickly diagnose the issue and offer prompt repair services.

Conclusion

Shallow well pump short cycling can be a frustrating problem, but understanding the technical specifications of your pump and the common causes of the issue can help you diagnose and fix the problem. By following the steps outlined in this guide, you can identify and address the root cause of the short cycling, ensuring your shallow well pump operates efficiently and reliably.

References:
Pump is Short Cycling Very Short
Why is My Well Pump Short Cycling?
Why is My Shallow Well Jet Pump Cycling On and Off Rapidly?