Common Dishwasher Problems We Fix

Dishwashers are hardworking machines that combine water, heat, and electricity. When they fail the symptoms are usually obvious but the causes can vary. Here are the most common issues we resolve for our neighbors in Sudbury.

Dishwasher Is Not Draining

One of the most frequent calls we receive is for a dishwasher that leaves a pool of standing water in the bottom of the tub after the cycle ends. This creates odors and prevents you from running a new load.

Likely causes:

• Clogged drain filter or sump area
• Blocked drain hose or air gap
• Failed drain pump
• Broken drain impeller
• Garbage disposal knockout plug not removed (on new installs)
• Check valve stuck closed

How we diagnose it:

We start by inspecting the filtration system for debris like glass shards or food particles. We listen to the drain pump to see if it hums without moving water which indicates a jam or failure. We also check the entire drain path from the pump to the sink connection to ensure there are no kinks or clogs restricting flow.

What you can do right now:

Check the filter at the bottom of the tub and remove any large debris. If you have an air gap cylinder on your sink counter check that it is not blocked. Ensure your garbage disposal is clear if the dishwasher drains into it.

Dishwasher Is Leaking Water

Water on your kitchen floor is a serious issue that can cause structural damage if ignored. Leaks can occur from the front door or from underneath the unit where components are hidden.

Likely causes:

• Worn or torn door gasket seal
• Loose hose clamp or connection
• Cracked water inlet valve
• Leaking drain pump or circulation pump seal
• Float switch stuck in the down position
• Using too much detergent creating excessive suds

How we diagnose it:

We remove the bottom toe kick panel and run a test cycle to observe the underside of the machine with a flashlight. We look for drip trails on hoses and pumps. We also inspect the door seal for rips or mineral buildup that might prevent a watertight seal.

What you can do right now:

Check the door seal for any food debris and wipe it clean. Verify that you are using the correct type of detergent. If the leak is severe turn off the water supply valve under the sink leading to the dishwasher.

Dishes Are Not Getting Clean

If you open the door to find food baked onto plates or a gritty residue on glasses the machine is not doing its job. This is often related to water flow or temperature.

Likely causes:

• Clogged spray arm holes
• Broken spray arm support or bearing
• Circulation pump failure
• Water inlet valve not opening fully
• Detergent dispenser not opening
• Hard water mineral deposits

How we diagnose it:

We listen for the sound of water spraying against the door during the wash cycle. We check the water level inside the tub to ensure it is high enough to reach the pump intake. We also inspect the spray arms to ensure they spin freely and are not blocked by tall dishes.

What you can do right now:

Run the hot water at your kitchen sink before starting the dishwasher to purge cold water from the line. Clean the spray arm holes with a toothpick to remove any seeds or lime scale.

Dishwasher Will Not Start

A dead dishwasher is frustrating. You press the start button and nothing happens or the lights might flash but the cycle never begins.

Likely causes:

• Defective door latch or door switch
• Blown thermal fuse
• Main control board failure
• User interface or touchpad ribbon cable failure
• Tripped circuit breaker
• Child lock feature activated

How we diagnose it:

We test the door switch for continuity to ensure the machine knows the door is closed. We check the thermal fuse which is a safety device that cuts power if the unit overheats. We also test the power supply entering the control board to rule out household electrical issues.

What you can do right now:

Check your home circuit breaker panel to see if the breaker has tripped. Try pressing the cancel button to reset the control board. Make sure the door is latched firmly.

Dishwasher Is Making Loud Noises

While modern dishwashers are quiet a sudden grinding, thumping, or squealing noise indicates a mechanical problem that needs attention.

Likely causes:

• Debris like bone or glass in the drain pump chopper
• Worn wash pump bearings
• Spray arm hitting dishes
• Loose drain hose rattling against the cabinet
• Broken motor impeller

How we diagnose it:

We identify when in the cycle the noise occurs. A noise during draining points to the drain pump while a noise during washing points to the circulation motor. We often disassemble the pump housing to check for foreign objects.

What you can do right now:

Check that the spray arms can spin without hitting any tall plates or silverware. Inspect the bottom of the tub for any hard objects that might be vibrating.

Dishwasher Is Not Drying Dishes

Opening the door to dripping wet dishes means you have to hand dry everything. This issue is common in energy efficient models but can also indicate a component failure.

Likely causes:

• Heating element burned out
• Vent fan assembly failure
• Rinse aid dispenser empty or broken
• High limit thermostat tripped
• Control board heater relay failure

How we diagnose it:

We test the heating element for continuity using a multimeter. We check the vent system to ensure moist air can escape. We also verify that the rinse aid dispenser is releasing fluid which is critical for drying in modern tub designs.

What you can do right now:

Ensure the rinse aid reservoir is full. Try using the “Sanitize” or “High Temp” option to increase the final rinse temperature which helps with evaporation.

Dishwasher Soap Dispenser Not Opening

Finding a solid cake of detergent still in the cup after the cycle means the soap never entered the wash water.

Likely causes:

• Broken spring or latch on the dispenser door
• Wax motor actuator failure
• Detergent build up jamming the cover
• Tall dishes blocking the dispenser door
• Timer or control board failure

How we diagnose it:

We inspect the mechanical linkage of the dispenser door. We test the actuator that triggers the door to open at the right time in the cycle. We also check the alignment of the door.

What you can do right now:

Make sure the dispenser cup is dry before adding powder. Ensure no large plates or cutting boards are placed right in front of the dispenser.

Dishwasher Runs Too Long

If your dishwasher cycle is taking three or four hours it might be struggling to heat the water or sense that the dishes are clean.

Likely causes:

• Faulty temperature sensor or thermistor
• Heating element not working (causing water heat delays)
• Dirty optical soil sensor
• Low incoming water temperature
• Cycle selection settings

How we diagnose it:

We check the resistance values of the temperature sensor. We clean the optical sensor that determines how dirty the water is. We also verify the operation of the heating element which maintains water temperature during the wash.

What you can do right now:

Run the hot water at the sink before starting the load. Check that you have not accidentally selected a “Heavy Duty” or “Sanitize” cycle if you only need a normal wash.