Sump pump troubleshooting: How to easily fix common failures

Having trouble with your sump pump? Before you spend hundreds of dollars getting your pump fixed,  you should first take a jab at fixing it. It might not be as hard or as messy as it sounds.

In this article, I’ll share with you sump pump troubleshooting procedures for the most common sump pump failures. Most of them are super simple and takes less than a few minutes of work. So why not give it a try.

Just remember, unplug the pump from the outlet before you go anywhere near it. Let’s start!

Table of Contents

Troubleshooting Sump Pump Failures

Sump pump will not start

1. Stuck or faulty float switch

A stuck or faulty float switch may prevent the pump from starting. If the switch doesn’t go up despite a high water level, check if it’s stuck or if the float ball has a hole where the water has entered.

If you have a piggyback switch, where you have two cords that lead to the outlet, you can try removing the plug of the pump and plugging it directly into the outlet just to see if the pump will run. If it does, the switch has a problem and may need replacement.

It will not start if the breaker trips or a fuse is blown. Try plugging the pump to a different outlet and see if it starts. Reset the breaker or replace the fuse and see if the pump starts.

If you’re using an extension cord, which most manufacturers advise against, make sure it’s at least rated to handle the amount of power your pump needs.

2. There's no power

Your typical pump runs on the outlet’s electricity and will not start if the breaker trips or a fuse is blown. Try plugging the pump to a different outlet and see if it starts. Reset the breaker or replace the fuse and see if the pump starts.

If you’re using an extension cord, which most manufacturers advise against, make sure it’s at least rated to handle the amount of power your pump needs.

3. Impeller is jammed

A large object may get inside the pump and block the impeller from turning. Unplug the pump and inspect for any debris stuck inside the impeller. After removing the debris, check if the impeller can freely rotate.

Sump pumps are meant to be used only for clear underground water. If you need to discharge water with solids or the water from your laundry, you’re better off getting an effluent pump or risk damaging a perfectly good sump pump.

4. Overheated motor

The pump may have overheated and tripped itself to protect the motor. The motor can overheat if there’s too much water and the pump has to run continuously for very long periods of time. If that’s the case, you may need a larger pump.

On the other hand, it may also overheat from an on and off cycle that’s too short which doesn’t allow it to cool off properly before having to start back up again. In such cases, a small sump pump or a larger sump pit is needed.

5. Damaged motor

Constant overheat or a failed thermal overload switch may result in a damaged motor. Determine the cause and replace it with a more appropriate sump pump. To protect your basement in such cases, it’s advisable to install a backup sump pump to pick up the job.

Sump pump is always running even without water

1. Stuck or faulty float switch

The float switch may get stuck at a high level due to dirt accumulation or rust formation. Try to clean up any accumulation and exercise the switch. Replace the switch if it has punctures or is malfunctioning for no other visible reasons.

If you have a piggyback switch, where you have two cords that lead to the outlet, you can try removing the plug of the pump and plugging it directly into the outlet just to see if the pump will run. If it does, the switch has a problem and may need replacement.

2. You have a piggyback switch

If you have a piggyback type switch, where the pump and the switch each have a cord, make sure that the pump’s plug is attached to the back or the side of the switch’s plug for proper operation.

3. It's a non-automatic pump

Check your pump’s model number on the internet and confirm if it’s an automatic pump. Non-automatic pumps always run when plugged in even when there’s no water.

You can buy a switch to automatically control the operation of the pump if this is the case.

Sump pump is running but the water level doesn’t go down

1. Pump is airlocked

Most sump pumps require a weep hole installed. That’s a 3/16″ hole drilled into the discharge pipe just below the cover of the sump basin. This allows air to bleed out of the hole so that the water can be moved without a problem.

2. Check valve is stuck or installed backwards

Sometimes, a check valve may get stuck in the close position due to manufacturing defects or dirt accumulation. You can try to disconnect the check valve then inspect, clean, and exercise it manually.

If you notice some defect, it’s best to replace the valve to avoid future troubles.

3. Clogged suction, impeller, or discharge

Discharge of the pipes may get clogged when debris collects or ice accumulates at some point in the line. A blocked intake hole is also common if there’s debris getting into the sump. It can also happen when the base or strainer corroded or accumulated dirt.

Try to clean off the accumulation and keep debris from getting into the sump in the first place.

If your water has high mineral content but isn’t that prone to debris, try a pump without a strainer or a base that’s not made with cast iron.

4. Frozen discharge

The water at the pipeline near the discharge may get frozen during winter blocking the water from your pump. Make sure the pipe outside slopes downward to avoid water accumulation and provide insulation to the pipe if possible.

5. There's a leak

If the pump or the discharge pipe has a leak, the pump may have trouble clearing the water out. Check for any signs of this by pulling the pump out.

6. You have an undersized pump

If you notice the pump running for a long time without clearing out the water, you may have an undersized pump. This can overwhelm the motor especially if it’s not rated for continuous duty.

Get a sump pump with a larger HP or try to reduce the amount of water getting into the basement.

7. Discharge pipe is too small

Having a smaller discharge pipe line may save you a few dollars but it may impede the pump from giving the maximum capacity it can provide.

8. Low voltage

A low voltage can cause the pump to be underpowered. Try the pump in another outlet or contact an electrician.

Sump pump starts and stops often

1. Short on-and-off range

A very short distance between the on and off points may cause short cycling. You can try to adjust the range depending on the switch, you can check the manual for instructions. If you can’t, try to replace the switch with one that has an adjustable switch or one that has a better range.

2. Your basin is too small

An undersized basin may cause the pump to turn on and off frequently which will eventually overheat the motor. Try to get a larger basin if possible so more time will be available between the on and off cycles.

3. Your pump is too large

An oversized pump is the other side of the problem. If you have a decent sized pit but an overpowered pump, the pump will clear the water out too fast resulting in shorter on and off cycles. Get a smaller pump that fits your situation better.

4. There's no check valve installed or it's stuck

The check valve keeps the water that has passed through it from going back into the pit. Without a check valve, the water that goes back will cause the sump pit to fill up faster resulting in frequent cycling of the pump.

5. There's too much water coming in

If there’s too much water coming into the sump, the pump may need to run more often. Protect your basement with a sump pump alarm to notify when the water is about to overflow and try to find out the cause of the incoming water. The common reasons for include:

  • The ground outside is sloping towards the house
  • Clogged gutter
  • Short downspout
  • Cracks in foundation walls
  • High water table

The pump runs for awhile then stops before the off point ​

1. It's overheating

Some sump pumps have a thermal overload trip that stops the pump from running to protect the motor from getting burnt. The motor can overheat if there’s too much water and the pump has to run continuously for very long periods of time. If that’s the case, you may need a larger pump.

On the other hand, it may also overheat from an on and off cycle that’s too short which doesn’t allow it to cool off properly before having to start back up again. In such cases, a smaller pump or a larger pit is needed.

2. Faulty switch

If the switch has a loose contact on its circuitry or is just defective, it may cause improper operation of the pump. Replace the switch with a new one.

Excessive noise​

1. Impeller is broken

A broken impeller may cause imbalance to the pump and therefore create noise. Replace the pump with one that has a more durable impeller and keep solids away from the sump pit. Also, make sure your check valve is working correctly since it could be the reason for the damage.

2. Worn out bearings​

The bearings may get worn out after a few years of service or if the lubrication is no longer in good condition. This can cause the pump to create noise as bearings help to reduce friction and imbalance that can create noise.

3. Water hammer

As the pump starts and stops, the water moves abruptly in the pipes creating shock waves. You can install a silent type check valve that has a spring, which gently opens or closes the flapper, to help minimize the noise. Also, check if the pipes are supported properly — not too loose or too rigid — to help reduce the vibrations.

4. You have a pedestal type pump

The pedestal type sump pump has an exposed motor that may create distracting noise. Try to make sure the pump is properly fixed in place as that may add to the noise created. A submersible sump pump is a great alternative if you want a sump pump that’s really quiet since it stays under the water.

Conclusion

Well that covers most of the common problems with sump pumps. I hope you’ve fixed the problem with the pump (although if you’re still reading the conclusion, then probably not). You can hit us up in the comments below if you have any questions. Maybe a few experts would be willing to share some advice.

You also try to contact your manufacturer since it could be a problem that’s common with their product. But if you’re out of time, contacting your plumber would be best. They know your system and will probably have a better understanding of it than anyone.

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