Tackling a repair on a Whirlpool dishwasher might seem intimidating, but with the right approach, it is highly manageable. This protocol is rated at a Easy difficulty level and is designed to walk you through the diagnosis and fix. Armed with basic tools like Small brush and Vinegar, you can expect to spend roughly 30-45 min resolving the problem without the need for an expensive service call.
Difficulty: Easy • Est. Cost: Varies • Time: 30-45 min
Safety Warning: This technical guide follows the official field diagnostic sequence. Ensure power is disconnected before performing any internal component tests.
1. Inspection of Spray Arms
Food particles often get trapped in the small jet holes of the spray arms. These holes are small enough that even a single grain of rice can block them, preventing water from reaching specific areas of the dish rack.
- Remove the lower spray arm by turning the center hub counter-clockwise. The upper spray arm is typically held by a threaded retaining nut or a snap-ring — turn it clockwise to release.
- Check the upper and middle arms for blocked holes using a flashlight. Shine the light through each arm from the hub end — you should see light coming out of every jet hole.
- Use a toothpick or small brush to clear any debris from the spray nozzles. Do not use a metal wire or pin — it can scratch the plastic and create rough edges that trap more debris.
- Check the spray arm bearings — the arm should spin freely with a gentle flick. If it feels gritty or stiff, the bearing is clogged with hard water deposits. Soak the arm in white vinegar for 30 minutes to dissolve the scale.
2. Cleaning the Triple Filtration System
Whirlpool's triple filter system is highly efficient at trapping food particles, but it needs regular maintenance. If the filters are clogged, water circulation is restricted and dishes come out dirty.
- Turn the upper filter assembly 1/4 turn counter-clockwise and lift it out. This is the fine mesh filter that catches small particles.
- Gently pull the lower filter (the flat plate with large holes) away from the bottom of the tub. This filter catches larger food scraps before they reach the drain pump.
- Rinse both filters under warm running water. Use a soft brush to remove stubborn debris from the fine mesh. If white mineral scale is visible, soak the filters in white vinegar for 15-20 minutes.
- Inspect the filter housing inside the dishwasher — use a flashlight to look for broken glass or debris lodged around the sump opening. Remove any debris with needle-nose pliers.
- Reinstall the filters in the correct order: lower coarse filter first, then upper fine filter with a clockwise turn to lock.
3. Clean the Wash Impeller and Sump
Behind the filter assembly is the wash impeller — the spinning disc that pressurizes water to the spray arms. If the impeller is clogged with stringy debris or hardened grease, water pressure drops dramatically.
- Remove the fine and coarse filters. Look down into the sump opening — you will see the impeller disc. It should spin freely and have clean vanes.
- Use a Torx T15 screwdriver to remove the small plastic cover protecting the chopper blade (the blade that grinds food particles before draining).
- Clean out any tangled debris — dental floss, hair, stringy vegetable matter — that is wrapped around the chopper blade or impeller hub. This debris acts like a brake, slowing the impeller and reducing water pressure.
- If the impeller vanes are chipped or broken, replace the entire sump assembly (Whirlpool part W11405816). Damaged vanes cannot build adequate water pressure.
4. Check the Drain Pump and Check Valve
A partially blocked drain pump can cause dirty water to backflow into the tub during the wash cycle, redepositing food particles on your clean dishes.
- Access the drain pump by removing the lower kickplate (two Torx T20 screws). The pump is a black plastic unit on the left side of the base.
- Remove the drain hose from the pump and check for blockages. A common cause of backflow is a failed check valve — a small rubber flap inside the drain hose connection that prevents water from flowing backward.
- Test the check valve by blowing into the drain hose from the pump end. Air should pass freely in one direction (outward) but not the other. If air passes both ways, the flap is worn and the hose assembly needs replacement.
- If the pump itself is clogged, remove the pump cover and extract debris from the impeller area. Reassemble and run a rinse cycle to verify drainage.
5. Run a Deep Clean Cycle and Check Detergent
Grease buildup in the internal plumbing is a common cause of poor cleaning on Whirlpool dishwashers. Run a dishwasher cleaner treatment once per month to prevent this.
- Place a dishwasher cleaner tablet (such as Affresh or Finish Dual Action) in the silverware basket, not the detergent dispenser. Run the hottest cycle available (usually Sani Rinse or Heavy Duty).
- Check that your detergent is fresh. Old or clumpy detergent loses cleaning power. Use a high-quality detergent like Cascade Platinum or Finish Quantum — these contain enzymes that break down food proteins.
- Ensure the rinse aid dispenser is filled. Rinse aid improves drying and prevents water spots, but it also helps water sheet off dishes rather than beading up and leaving residue.
- Verify the water temperature entering the dishwasher is at least 120°F. Run the kitchen faucet hot for 30 seconds before starting the dishwasher to purge cold water from the pipes.
6. Check Water Pressure and Inlet Valve
Low water pressure can prevent the spray arms from rotating properly, resulting in poor cleaning. Whirlpool dishwashers require a minimum of 20 psi for proper operation.
- Run a cycle and open the door after the first fill (about 5 minutes in). Look at the water level — it should cover the heating element at the bottom of the tub. If the water level is low, the inlet valve may be restricted.
- Check the water inlet valve screen (located at the connection point under the dishwasher). Shut off the water supply and disconnect the hose — the screen is inside the valve port. Clean it with a small brush.
- If the screen is clean but water flow is still slow, test the inlet valve solenoid for continuity (200-500 ohms is normal). A failed solenoid will not open the valve fully.
- For persistent low water pressure, check your home supply. A partially closed shut-off valve under the sink or a clogged supply line can restrict flow to the dishwasher.