Why Is My Pump Working but Water Not Circulating

Is your pump running but not circulating water? Obstructed pipes, airlocks, and valve malfunctions can all prevent proper water flow.

Left unresolved, these issues can lead to pump damage, reduced efficiency, and costly repairs or replacements.

By troubleshooting common causes like clogs, air leaks, impeller problems, and low water levels, you can quickly identify and fix circulation issues to keep your pump running smoothly.

Obstructions in the System

When a pump is running but water isn’t circulating, the first place to check is for obstructions in the system that could be impeding water flow:

• Intake strainer and filter baskets: Clogged or dirty intake strainers and filter baskets are a common culprit. Clean out any debris or buildup.
• Pump impeller: The impeller can become clogged with debris, preventing it from properly moving water. Inspect and clean the impeller.
• Discharge pipes and outlets: Look for blockages or restrictions in the pipes and outlets where the water is discharged from the pump. Clear any obstructions.
• Sediment filters: If the system has sediment filters, check if they have become excessively dirty and are restricting flow. Clean or replace as needed.

The Impact of Air

Air in the pump system can also prevent proper water circulation, even if the pump is running.

• Airlocks: If air becomes trapped in the high point of the discharge pipe, it can create an airlock that stops water flow. Bleed the air out of the system.
• Low water levels and air intake: If the water source level drops too low, the pump may start sucking in air instead of water, interrupting flow. Ensure adequate water levels.
• Priming the pump: Upon initial startup, pumps need to be primed by adding water so they don’t just suck air. Make sure the pump is primed with water.

Valve Malfunctions

Valves play an important role in controlling water flow and direction. Malfunctioning valves can give the appearance that the pump isn’t circulating water:

• Check valves for preventing backflow: Check valves ensure water only flows in one direction. If they are stuck or installed backwards, water may be flowing the wrong way. Inspect and replace faulty check valves.
• Intake and discharge valves: The valves on the intake and discharge sides of the pump must be in the open position for water to circulate. Verify these valves are open and functional.

Impeller Problems

The impeller is the heart of the pump, and if it isn’t working properly, water flow will be diminished or stopped completely:

• Impeller damage and wear: Over time, impellers can become damaged, eroded or worn, reducing their ability to move water. Inspect the impeller for signs of wear and replace if needed.
• Debris and obstructions: In addition to clogs, debris can actually damage the impeller and diminish performance. Remove any debris and ensure the impeller is in good condition.
• Loose impeller: If the impeller has worked loose from the shaft, it won’t be able to generate enough force to pump the water. Check that the impeller is secure and tighten if necessary.

Source Water Issues

Sometimes, the problem originates not with the pump itself but with the source of the water it is trying to circulate:

• Wells running dry: If the pump draws from a well, the well may have run dry or the water table dropped too low for the pump to draw from. Test well water levels and deepen the well if needed.
• Low water levels in pools or tanks: For pumps that draw from pools, tanks or cisterns, low water levels may be allowing the pump to suck in air. Keep water levels high enough for the pump to function.

Other Potential Causes

If none of the above issues seem to be the problem, there are a few other potential causes to investigate:

• Electrical issues: Problems with the electrical supply to the pump, such as reversed polarity causing the impeller to spin backwards, can impact water flow. Have an electrician inspect the wiring and motor.
• Mechanical failures: Major mechanical failures inside the pump, such as a broken coupler between the motor and pump housing, can prevent the impeller from turning. Diagnose and repair mechanical problems.
• Incorrect pressure settings: For pumps with adjustable pressure switches, incorrect settings may be preventing the pump from generating enough pressure to circulate the water. Adjust settings as needed.