Submersible Pump Not Working? A Safe, Step-by-Step Troubleshooting Guide

A faulty submersible pump can feel like a disaster waiting to happen—standing water in your basement, no water flow from your well, or a pump that simply won't turn on. But before you panic and call a professional, take a deep breath. Many common pump issues can be fixed safely with the right approach and tools. This step-by-step troubleshooting guide will walk you through diagnosing and fixing problems with your submersible pump.

Safety first: Since electricity and water are involved, there's an element of risk. If you're not confident or encounter major issues, it's best to call in a licensed expert.

Quick Problem Reference Guide

Here's a snapshot of common symptoms and likely causes to get you started:

• Won't start → Tripped breaker, bad float or pressure switch, failed capacitor.

• Hums but doesn't pump → Clogged impeller, blocked intake, stuck check valve.

• Runs with low flow → Clogged screen, worn impeller, leaking pipe.

• Short cycles → Faulty pressure switch, waterlogged tank, leaking check valve.

• Trips breaker → Ground fault, motor seizure, damaged electrical splice.

Follow along as we break down step-by-step instructions to identify and fix these problems.

Know Your Pump & Setup

Before you troubleshoot, it's important to know your system. Different types of submersible pumps serve various purposes:

• Sump Pumps—Remove standing water in basements or pits.

• Sewage/Grinder Pumps—Handle wastewater or solids.

• Well Pumps—Pull water from deep wells.

• Utility Pumps—Use for general water movement, like dewatering or draining tanks.

Regardless of the type, most pumps share common components, including a power cable, float or pressure switch, check valve, and discharge piping. Familiarizing yourself with these parts can make troubleshooting easier.

Safety First

Before taking any steps, prioritize your safety:

• Disconnect power: Always unplug the pump or turn off the breaker before touching any components.

• Test for live electricity: Use a non-contact voltage tester to verify if the electrical supply is off.

• Wear PPE: Insulated gloves and dry conditions are critical to avoid electric shocks.

• Avoid lifting the pump prematurely: Many submersible pumps are heavy—use proper lifting straps or tethers if removal becomes necessary.

If your work space is confined, has combustible gases, or you detect hazardous smells like hydrogen sulfide, leave the area and consult a professional.

Step-by-Step Troubleshooting

Step 1: Verify the Power Supply

If your pump won't start, a power issue might be the culprit.

• Check if the circuit breaker or GFCI outlet has tripped. Reset it if necessary.

• Test the outlet with a voltmeter to ensure it’s delivering power. If an extension cord is used, verify it isn't damaged or overheating.

• Look for visible signs of damage along the power cable, like cuts, melted insulation, or frayed strands.

Step 2: Inspect the Controls

Most submersible pumps use either a float switch (sump and sewage pumps) or a pressure switch (well pumps). Here's how to examine them:

• Float Switch: Pull the float up and down to ensure it moves freely. Remove any debris or tangles preventing proper function. If that doesn't work, test continuity with a multimeter.

• Pressure Switch: Manually adjust the switch to ensure it clicks on and off at the proper settings. Replace worn or corroded pressure contacts if needed.

Step 3: Listen and Observe

• No sound? There may be a power failure or control issue.

• Humming but not pumping? The rotor may be jammed or a capacitor might have failed.

• Clicking on and off (short cycling)? This often indicates a check valve leak, waterlogged tank, or incorrect pressure switch settings.

Step 4: Test Electrical Components

For electrical health, testing with specialized tools may be required:

• Use a multimeter to check the start and run capacitors for proper ratings.

• Inspect resistance in the motor windings using a megger tester. Low insulation resistance could indicate moisture ingress or internal faults.

• If thermal overload protection has tripped, allow the motor to cool before resetting it.

Step 5: Inspect the Hydraulic Path

Water flow problems are frequently caused by blockages or restrictions. Check:

• Intake screen: Remove accumulated debris, sand, or muck that clogs the intake.

• Discharge line: Look for kinks, frozen sections, or signs of airlock.

• Check valve: Ensure it's oriented correctly and the flapper isn’t stuck or leaking back.

Step 6: Assess Mechanical Components

If everything checks out and the pump still doesn't work, mechanical issues could be to blame:

• Impeller blade wear: Open the pump housing to check for damaged or worn blades. Clear away gritty deposits that might cause binding.

• Motor seals: Look for leaks. Milky or cloudy oil in oil-filled units is often a sign of water contamination.

• Bearings: Excess vibration or noise could indicate bearing failure.

Step 7: Pull the Pump (If Necessary)

If all else fails and it's safe to proceed, you may need to remove the pump for thorough inspection. Always lift the pump using designated tethers or straps to avoid damage to cables or fittings. Test the motor outside the well or pit for smoother diagnostics.

Common Fixes You Can Do

Certain repairs can be handled without a professional:

• Clean the intake screen and clear clogged sections of the discharge line.

• Replace damaged or stuck float switches. Adjust the tether length to prevent tangles.

• Install a new external check valve and ensure it's placed vertically.

• Repair damaged splices using waterproof heat-shrink kits.

• Swap out defective capacitors—ensure you match specs before installation.

When to Call a Professional

Some problems are beyond DIY territory. Contact a professional if:

• Your breaker keeps tripping.

• A megger test shows motor insulation failure.

• The motor shaft appears locked or seized.

• You can smell hazardous gases, like hydrogen sulfide.

• The pump is submerged in a confined or unsafe space.

Preventive Maintenance Tips

Preventing pump issues saves time and money:

• Clean sump pits and well screens quarterly.

• Test your pump regularly to ensure proper cycling.

• Replace check valves and float switches at recommended intervals.

• Install surge protectors and GFCI units to safeguard electrical components.

Troubleshooting Made Easier with a Visual Flowchart

For faster navigation, use this handy decision flow:

• Submersible pump won't start? Check power, control switches, and capacitors.

• Humming but no pumping? Inspect the impeller, intake, and check valve.

• Low flow or pressure? Remove clogs, clean screens, and look for leaks.

Tools Checklist for DIYers

Before starting, ensure you have the right tools:

• Non-contact voltage tester

• Multimeter

• Insulated screwdrivers

• Replacement float or pressure switch

• Waterproof splice kit

• Tether/rope for lifting

• Proper PPE (gloves, boots, goggles)

Final Thoughts

Submersible pumps are reliable workhorses when maintained properly. This guide gives you the tools and steps to diagnose problems safely, address common fixes, and know when to seek professional help. Take care of minor issues promptly to extend the pump's life and ensure smooth operation.

Got troubleshooting tips or experiences to share? Drop us a line! And if you need high-quality replacement parts, check valves, or switches, explore our product catalog today.