The short answer
On the ZMWDUHA line, dishes that come out gritty, filmed or still wet are almost always a water-delivery problem rather than a failed machine: something is stopping hot water reaching every surface at pressure. On this page loading and detergent come first, because a machine blamed for poor cleaning is often being asked to do the impossible. Work from the water path inwards — filter, arms, fill, temperature — before anything is suspected of being broken.
What an owner actually observes on the ZMWDUHA line
- The top rack comes out dirty and the bottom rack clean — The upper spray arm is not turning or not being fed — a classic split that names the fault by itself.
- The detergent cup is still full at the end of the cycle — The door of the cup never opened, or it was blocked by a tall item on the lower rack.
- NEAR MISS — dirty dishes plus standing water in the bottom — That is a drainage fault, and it belongs on the drainage page: dirty water left in the tub gets pumped back over the load.
The ranking for the ZMWDUHA line, likeliest first
- Loading, detergent or rinse aid — Ranked first because it costs nothing to correct and because it produces every symptom on this page: shadowed items, an unopened detergent cup and poor drying all follow from how the racks were packed.
- The filter and sump are loaded with debris — A silted filter passes debris back into the spray water. It ranks here because the checks above it are quicker, not because it is uncommon.
- The incoming water is not hot enough to dissolve detergent — Detergent needs heat to work at all, and a machine drawing lukewarm water films glassware instead of cleaning it. It ranks mid because it is a supply question rather than an appliance one.
- A spray arm is blocked, or is not free to turn — Low here only because the reported symptom is uniform rather than split across the racks.
The diagnostic order, and the reason for it
- First — reload the racks and check the detergent — Nothing tall in front of the detergent door, nothing nested, and detergent from an opened packet that is still fresh. Top up the rinse aid while you are there.
- Then — lift the filter out and rinse it — Twist the cylinder free, take the coarse screen with it and rinse both under a hot tap. Look in the sump for glass, labels and seeds while it is open.
- Only then — run the kitchen tap hot before starting a cycle — A machine that fills from a long cold run starts every wash behind. If cleaning improves after this, the supply is the fault and not the appliance.
- STOP here if the next check needs a panel off or a meter on live terminals — Everything above can be done with nothing dismantled; past it the checks need test equipment.
Read this before any panel comes off
Safety
Unplug the appliance or switch off its breaker before removing the kick plate or the inner door panel — a capacitor can hold a charge after the power is off, and the control and heater terminals sit within reach of standing water. Close the supply shut-off under the sink before disturbing any fitting, and never reach into the sump while the machine is powered: the chopper and the drain impeller start without warning.
When it stops being an owner job
Call when the arms turn freely, the filter is clean and the fill is full and the load still comes out dirty — at that point the circulation pump or the diverter is the candidate and both are behind the tub. On the ZMWDUHA line, call rather than continue if the sump has to come out. Call sooner if the machine trips the breaker, if there is water under the kick plate, or if you can smell burning during the dry phase.
Other faults covered for the ZMWDUHA line
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
