Monogram Dishwasher Upper Rack Not Cleaning: Why the Top Stays Dirty

Cups with a film, plates with dried-on food, and bowls that look barely rinsed are common complaints when the upper rack is not getting its share of water. The lower rack often works because water sprays upward from the bottom arm with little effort. The upper level depends on a separate path that is easier to disturb.

How water reaches the top rack

Most dishwashers send water through more than one spray arm. A lower arm sprays the bottom rack and splashes upward, while an upper or mid-level arm sprays the top rack from below or from above. Water is carried to the upper arm through a channel or tube. If that channel is clogged, loose, or misaligned, the upper arm turns weakly or not at all, and the top rack gets less cleaning.

Seeing which items stay dirty helps. If the whole upper rack is poor, the arm or its feed is suspect. If only one corner fails, something may be blocking a spray, for example a tall item or a handle hitting the arm.

Loading and rack position

Start with how the rack is loaded. A tall platter, a large bowl, or a cutting board can sit across the path of the arm and stop it from rotating. Run your hand around the arm with the dishwasher off to confirm it turns freely. Tall items on the lower rack can also block the water that would otherwise splash up.

Check that the upper rack is seated on its rails and that its connector for the upper arm, if there is one, is lined up. Racks that have been removed for cleaning sometimes go back slightly off, and the water feed to the upper arm does not connect fully. Wipe the connection area and push the rack home until it settles.

Spray arm holes and the filter

Hard water minerals and food particles clog the small holes in a spray arm. With the dishwasher off, look closely at the holes on both the upper and lower arms. If they hold debris, remove it with a toothpick or soft brush after taking the arm off according to your manual. Rinse the arm and replace it so that it spins freely.

The filter in the bottom of the tub also matters. A clogged filter reduces the water available for the pump, and the arm that is farthest from the pump suffers first. Rinse the filter assembly and check the tub floor for debris, with the power at the breaker off.

Dishwasher detergent type and load size matter too. A packed machine leaves little room for spray to reach every surface, and a detergent that does not dissolve leaves film on glasses.

Sensing and cycle length

Some models have a sensing light that evaluates how dirty the water is and adjusts the cycle. A code for that sensing, such as the one described on our CLEANSENSOR error page, means the sensing light does not come on at the start of the normal or pots and pans cycle, but the dishwasher keeps working. It is a useful note for a technician because a fault there may change how long the cycle runs for a given load.

If the cycle seems unusually short, or the dishwasher skips steps, write that down. It is part of the diagnosis.

What a technician tests

When the outside checks do not explain it, a technician looks at:

• The circulation pump and its ability to build enough pressure for the upper arm.
• The diverter or valve, if the model uses one, which sends water between the levels.
• The upper arm bearing or mount, which can wear or crack.
• The water inlet valve, if the tub is not filling enough.
• The heating element, since poor drying and poor washing often go together.
• The control board, if cycle times are incorrect.

Many of these produce the same symptom, which is why the diagnosis comes before a repair. You receive a written estimate and nothing is repaired without your approval.

Owner checks, in order

1. Run your hand around each spray arm to make sure it spins freely.
2. Check that no tall item blocks an arm.
3. Rinse the filter assembly and check the tub floor.
4. Clear the holes in the spray arms of mineral and food buildup.
5. Check that the upper rack is fully seated.
6. Run a short cycle with an empty top rack and see whether the water pattern is stronger.

What not to do

Do not use a wire or pin to enlarge the holes in a spray arm. Do not use a household cleaner containing bleach on stainless parts. Do not pack the lower rack to the edges to fit more. Do not remove access panels to reach the pump. If you smell burning, switch the breaker off.

Installation details that matter

Built-in dishwashers differ in rack design. A panel-ready model hides its controls on the top edge of the door, which can make it harder to see lights and codes. The 24-inch ZDT985SSNSS is a current minimalist model, and its racks and spray arms differ from those on older models. The first letters of the number tell us it is a dishwasher, and the rest helps match the parts.

In Bay Area kitchens with hard water or older plumbing, mineral deposits on spray arms and filters build up faster. If you notice a white film on glasses and inside the tub, a cleaning cycle for the machine and a check of the arm holes helps.

The model number is usually on the door edge or inside the tub. Our post on finding the model number before service shows where to look.

When to book

Book when the arms are clear and the filter is clean but the upper rack remains dirty, when the arm does not turn, or when you hear unusual noises during a cycle. Our Monogram dishwasher repair page explains the visit, and the Monogram dishwashers guide covers the lineup. If water also remains in the tub after the cycle, read our post on water in the bottom of a Monogram dishwasher.

Frequently asked questions