A sump pump that hums but does not pump water is not functioning correctly. This issue may be due to a blocked impeller, a stuck or broken float switch, or a problem with the discharge lines. Other potential causes include interruptions in the electrical supply, overheated pump parts, or incorrect installation of the pump.
Prompt diagnosis and repair are necessary to ensure the sump pump works effectively and to prevent water damage to the property.
Electrical Supply Issues
When a sump pump hums but does not pump water, it is likely due to electrical supply problems. This could mean the pump is getting some power but not enough to operate, or there may be an issue with the motor or wiring. If a sump pump continuously hums, it is important to check the power source and connections for any issues.
Inspecting the electrical connections is essential in sump pump repair. This involves checking the outlet for the correct voltage and examining the power cord for damage. If problems persist, a multimeter can be used to identify the specific electrical issue. The sump pump should also have its own circuit to avoid overloading and tripped breakers or blown fuses.
A humming noise might also signal that the motor is at risk of burning out, especially if the pump runs without moving water, which can cause the motor to overheat and fail. Quick action is necessary to prevent more damage to the sump pump. A professional repair service can determine the exact cause, replace faulty parts, and get the pump working properly to mitigate the risks of a malfunctioning sump pump.
Jammed or Clogged Impeller
A jammed or clogged impeller is often the reason a sump pump hums without pumping water. Debris such as sediment and small stones can block the impeller, the part that moves water out of the pit, causing the pump to malfunction.
Regular maintenance, including checking the impeller for wear or damage and removing any blockages, is crucial for sump pump functionality. A clogged impeller can lead to water buildup and potential flooding, especially during heavy rain. The motor may overheat or burn out if forced to work harder due to a blockage.
To fix a jammed impeller, turn off and unplug the sump pump. Remove the cover to access the impeller, clear any debris, and ensure it moves freely. After reassembling, plug the pump back in. If the impeller is damaged, it should be replaced.
Faulty or Stuck Float Switch
A stuck or defective float switch can cause a sump pump to hum without pumping water. The float switch activates the pump once the water level rises to a set point. If the switch is stuck or fails due to debris, sediment, or wear and tear, the pump won't start.
To prevent a stuck switch, regularly clean and inspect the sump basin. If the switch is stuck, unplug the pump and try to free it. If the switch is defective, it may need replacing. For replacement, consider hiring a professional.
Proper float switch function is essential for a reliable sump pump system to prevent flooding.
Obstructed or Blocked Discharge Lines
An obstructed discharge line is a common cause for a sump pump to hum without ejecting water. The discharge pipes that remove water from the sump basin can be clogged with debris, dirt, or ice, which stops the water from flowing out. This blockage creates back pressure on the pump, leading to a humming sound as the motor runs without pumping water.
A malfunctioning or missing check valve can also cause a blocked discharge line, as it is designed to prevent water from flowing back into the sump pit. If it does not close correctly, water can flow back into the basin, creating gurgling sounds and reducing the pump's efficiency. To replace a faulty check valve, one must loosen the clamps on the pipe above the sump basin and install a new valve for a proper seal and flow direction.
To prevent blockages, a relief hole is recommended between the pump and the check valve. This hole allows trapped air to escape, preventing air lock, which can result in continuous humming from the pump trying to move air instead of water.
Debris buildup at the discharge line's start, especially at the pump's outlet, can also cause humming. Regular inspections and cleanings are crucial to keep the flow unobstructed and the sump pump working properly.
Overheating and Thermal Overload
An obstructed discharge line can cause a sump pump to hum, but if the pump hums without moving water, it may be overheating and suffering from thermal overload. This is a serious issue that can result in motor burnout if not addressed quickly. A humming noise indicates that the motor is trying to work but is being hindered by a problem.
Overheating can be caused by various factors. Without a relief hole between the pump and the check valve, the pump can overwork, increasing overheating risk. Blockages in the pump or line can also restrict water flow, causing the motor to work harder and produce a humming noise. This stress can activate the pump's thermal protection, which shuts down the motor to prevent damage when it overheats.
To troubleshoot, unplug the pump, remove it from the pit, and check for clogs or debris on the impeller. Continuous operation without water movement can lead to motor burnout and insufficient water removal, possibly resulting in flooding or water damage.
Regular maintenance is crucial to avoid overheating and thermal overload. Homeowners should check for intake debris, clean the pump housing, ensure weep holes are clear, and replace any faulty check valves. These preventive steps can greatly decrease the likelihood of a sump pump humming due to overheating.
Damaged or Worn Bearings
Damaged or worn bearings in a sump pump can cause a humming noise while failing to move water. Bearings reduce friction in the motor and are crucial for the pump's operation. If they are damaged, the motor may hum but the pump won't be able to push water out effectively. This humming could be wrongly thought to be normal when it's actually a sign of mechanical issues, such as an air lock or resistance from bad bearings.
To avoid this, sump pumps need regular maintenance, including bearing inspections. If bearings are worn or damaged, they should be replaced immediately to prevent motor failure and the potential need for a new pump. Monitoring and maintaining bearings are vital for a sump pump's ability to remove water.
Incorrect Sump Pump Installation
Incorrect installation of a sump pump can cause operational issues, such as a humming sound with no water being pumped out. This may result from the pump not effectively channeling water into the sump basin, risking inadequate drainage and potential flooding. The lack of a check valve, needed to prevent backflow of water, can create a gurgling noise. If a check valve is too close to the pump, it may produce a banging noise due to water striking it during operation.
An air lock, which may cause a humming noise, occurs if there's no relief hole between the pump and the check valve. This can be corrected by drilling a hole in the discharge pipe to release the trapped air, allowing the pump to work correctly.
Proper installation ensures that the pump is correctly oriented and securely attached to the discharge line to prevent excessive vibration and possible damage. The pump's impeller must also be clear of debris to avoid blockages that prevent it from spinning, which can also cause humming.
Professional installation or adherence to manufacturer's instructions is crucial for the sump pump's longevity and efficiency.
