Dishwasher Hums But No Water Comes In? Solutions Here

Nothing is more frustrating than your dishwasher humming away but not actually washing the dishes. You load it up, press start, and instead of the familiar sound of water spraying, all you hear is an obnoxious hum. No matter how long it runs, your dishes remain dirty.

A dishwasher that hums but doesn't fill with water usually indicates a fairly simple problem. With some basic troubleshooting, you can likely get your appliance working again in no time.

Inspect the Water Supply Line Thoroughly

The first thing to check is the dishwasher's water supply line. Make sure it's securely connected to the shutoff valve under the sink and that the valve is turned completely on. Also examine the water supply hose for any kinks, cracks, or blockages that could restrict water flow.

Use a flashlight to visually inspect the interior of the supply line for sediment accumulation or debris. Scale buildup and mineral deposits are common inside the line and can significantly reduce water flow.

Flush the Supply Line

An effective way to clean out the supply line is to disconnect it from the dishwasher and shutoff valve. Place the line in a bucket and flush it out with a vinegar and water solution to dissolve any scale or debris. For stubborn clogs, use a drain snake or pipe cleaner brush to physically scrub out the interior of the line.

Once flushed, reconnect the supply line and perform a water flow test by running the tap. If flow remains low, inspect the shutoff valve for obstructions next.

Examine the Shutoff Valve

The angle stop valve that connects to the dishwasher's supply line can also become clogged with mineral deposits over time. Scale accumulation inside the valve can restrict water flow even when fully open.

Use a rag or brush to scrub the interior of the valve. Soaking in white vinegar overnight helps dissolve stubborn deposits. Partially close and open the valve several times to dislodge debris.

Replace the shutoff valve if cleaning fails to improve water volume. Match the replacement to the existing valve connection size and type.

Check the Float Switch

The float switch is responsible for regulating water intake by detecting the dishwasher's fill level. If the float gets stuck, it cannot accurately sense when the tub is full and will fail to shut off the water.

First, visually inspect the float switch for damage and make sure it moves freely up and down. Use a multimeter to test for electrical continuity between the switch contacts when activated. If no continuity, replace the faulty float.

Inspect Switch Wiring

Loose, damaged, or disconnected wires leading to the float switch can also disrupt proper operation. Remove the outer dishwasher panel to access the switch wiring. Check that wire connections are secure and intact.

Use caution when testing switch wires, as contact with live electrical current can occur. Always turn off power to the dishwasher at the breaker before handling wiring.

Reset the Switch

In some cases, sliding the float switch up and down several times can dislodge debris causing it to stick. After resetting the switch, run a short test cycle to confirm if water intake was restored. The float should move freely when water enters the tub.

Replace a Faulty Inlet Valve

The inlet valve controls water flow into the dishwasher. Sediment and hard water scale often accumulate inside the valve over time, preventing it from opening properly. A defective valve solenoid coil can also cause failure.

Carefully disconnect the valve from the supply line and remove it from the dishwasher housing for further inspection. Test the solenoid with a multimeter for electrical continuity. Lack of continuity indicates a bad solenoid requiring valve replacement.

Clean or Replace Valve

To clean the valve, soak it in white vinegar overnight to dissolve mineral deposits. Use a small pin or brush to scrub debris from the valve inlet opening. Rinse thoroughly before reinstalling.

If cleaning doesn't resolve water flow issues, replace the entire inlet valve assembly. Make sure the new valve matches the original connection size and thread type.

Check Electrical Connection

Loose wiring leading to the inlet valve solenoid can disrupt operation. Remove the outer dishwasher panel to access the valve wires. Check that connections are secure and not corroded. Faulty wires should be replaced.

Examine the Door Alignment

The door switch is an important safety mechanism that prevents the dishwasher from running with the door open. If the door is misaligned, it can press on the switch incompletely, causing a humming noise without water spray.

Inspect door hinge mounting, checking for loose screws or damage. Adjust the door alignment so it makes full, even contact with the door switch when closed. The switch should also be checked for functionality.

Test the Door Switch

Use a multimeter to check for electrical continuity between the door switch terminals when the door is closed. Continuity should be indicated. Lack of continuity when closed means the switch needs replacing.

For switch replacement, make sure to disconnect power first. Remove switch wires, mounting screws, and the switch assembly. Install the new switch and reconnect wires securely.

Check Door Latch Magnet

The door latch uses a magnet to engage the door switch when closed. If this magnet becomes dislodged or damaged, it can prevent proper door switch activation even if aligned correctly.

Inspect the Drain Pump

If the dishwasher drain pump continues running even after draining is complete, it can impede the tub from filling properly. This usually indicates an electrical problem with the pump's internal microswitches or wiring.

A technician can determine if the pump needs replacing by testing pump components and observing when the humming occurs during the cycle. Component replacement or wiring repair may resolve the issue.

Check Pump Mounting

Sometimes a loose drain pump mounting can cause the humming noise without spray. Make sure the pump is secured properly to the dishwasher base. Inspect the rubber pump mounts for deterioration and replace if excessively worn.

Remove and Clean Pump

For a thorough inspection, the drain pump may need removing from the dishwasher. Check the pump impeller spins freely and clean out any debris. Replace damaged impellers or housings.

Clean Clogged Dishwasher Filter

With regular dishwashing, small food particles inevitably accumulate in the dishwasher filter, obstructing water flow to the spray arms. This common issue causes humming without adequate spray.

Removing and rinsing the filter takes just minutes. Use a mild detergent and brush to dislodge grease and debris if needed. Upon replacement, make sure the filter is fully seated in the pump intake opening.

Prevent Filter Clogs

Rinsing dishes before loading helps minimize food particles that can clog the filter. Run an empty vinegar cycle every few months to clean the interior and break up grease buildup.

Check the filter after each load for any trapped debris. Clogged filters should be rinsed out immediately to maintain optimal water flow.

Install Filter Correctly

If the filter is not fully seated in the pump intake opening, restricted water flow can occur. Align the filter properly with the opening when replacing it. The filter should fit snugly in place.

Inspect Electrical Wiring

Faulty wiring is a common source of electrical problems that can cause a dishwasher to hum without spraying water. Issues like loose connections, corroded contacts, and shorted or severed wires can prevent proper operation.

Carefully inspect the wiring leading to components like the inlet valve, float switch, and pump. Repair any loose connections and replace damaged wires. Always disconnect power first.

Test Component Wiring

Use a multimeter to test wires at the connections of key dishwasher components. Check for continuity or resistance patterns indicating shorts or disconnected circuits. This can help identify problem wires not visible externally.

Replace Control Board

If wiring checks out, a defective control board could be the issue. The control board regulates dishwasher electrical systems. Replace it with an identical OEM board if faulty.

Clean the Drain Valve and Check Solenoid

The drain valve removes water from the tub after each cleaning cycle. Sediment buildup can obstruct valve operation. Its solenoid activates the valve electronically via the control board.

Remove any debris from the drain valve inlet using vinegar and a small brush. Also check that the valve solenoid is functioning properly using a multimeter continuity test. Replace a faulty solenoid with an identical OEM part.

Adjust Water Pressure

Low incoming water pressure, below 20 psi, can prevent adequate spray pressure. Install a water pressure regulator if pressure fluctuates widely or is under 30 psi.

Also make sure the dishwasher's fill hose doesn't have any tight bends or kinks restricting flow. Replace the hose if worn out or severely twisted.

Check House Water Pressure

Determine incoming home water pressure with a pressure gauge installed on the supply line. Consistently low pressure may indicate issues with the home plumbing that need addressing.

Contact a plumber if low pressure persists throughout the home's water supply. There could be obstructions affecting the entire system.

Preventative Dishwasher Maintenance

Performing regular dishwasher maintenance can prevent many water flow problems. Here are some useful tips:

• Clean the filter after each load
• Use a monthly dishwasher cleaner to reduce grease
• Promptly repair any leaks or moisture damage
• Only wash full loads and use recommended detergent amounts
• Run vinegar rinse cycles to freshen the interior
• Don't overload dishes or block spray arms

When to Call a Repair Technician

If you've tried the troubleshooting steps without success, call an appliance repair technician for assistance. They have the advanced tools and expertise to properly diagnose tricky dishwasher issues and malfunctioning components.

A humming dishwasher that won't fill with water is usually an easy fix. In most cases, the cause is a clogged filter, debris in the supply line, or faulty inlet valve that can be repaired with basic tools and maintenance.

Refer to this article when troubleshooting a humming dishwasher without spray. Our tips and solutions will help restore proper water flow and washing performance again.