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Error code reference

Ariston Dishwasher Error Code AL 05

Clogged filters alarm

Ariston codesAriston dishwasher codes

Clogged filters alarm - pressure switch contacts do not close after water fill and filter cleaning cycle fails; also triggered by wash motor circuit faults or pressure sensor contacts open during wash.

First step from the service manual

Check mesh plate, filter, and microfilter for clogs; also check wash motor primary/auxiliary starter connections and condenser.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What AL 05 means on a Ariston dishwasher

AL 05 on an Ariston dishwasher is a clogged filters alarm that triggers when the pressure switch contacts fail to close following the water fill and filter cleaning cycle. The control board initiates a fill and self-cleaning sequence, then monitors the pressure switch to confirm that water has reached the required level and that flow through the filtration system is unobstructed. If the pressure switch contacts remain open after this sequence completes, the board interprets this as a blockage in the filtration path and halts operation with the AL 05 fault.

The primary filtration components involved are the mesh plate, the main filter basket, and the microfilter. Debris accumulation across any of these components restricts water flow to the point where system pressure cannot build sufficiently to close the pressure switch contacts. This is the most common trigger for AL 05 and is addressed by removing, inspecting, and thoroughly cleaning all three filter elements before running any further diagnostics.

AL 05 can also be triggered by faults in the wash motor circuit rather than a physical blockage. Specifically, problems with the wash motor primary or auxiliary starter connections and a failed or degraded motor run capacitor (condenser) can prevent the motor from circulating water correctly, which again results in inadequate pressure and open pressure switch contacts during the wash phase. When filter cleaning does not clear the fault, the diagnostic focus should shift to the wash motor circuit, including connection integrity at the starter terminals and the condition of the motor condenser.

Source: manufacturer service documentation.

Common causes of AL 05

  1. 01

    Clogged mesh plate, filter, or microfilter

    Wiring / connection

    Food debris, grease, or scale buildup across one or more of the three filter components restricts water flow and prevents the pressure switch from closing after the fill and filter cleaning cycle. Remove all filter elements, rinse them under running water, and scrub with a soft brush before reinstalling.

  2. 02

    Pressure switch contacts stuck open

    Part replacement

    Even with clean filters, the pressure switch itself can fail to close its contacts if the diaphragm is damaged or the switch mechanism is faulty. If cleaning the filters does not clear AL 05, the pressure switch should be tested for correct contact closure at the expected water level.

  3. 03

    Faulty wash motor condenser (capacitor)

    Part replacement

    A degraded or failed run capacitor on the wash motor prevents the motor from reaching full operating speed, reducing water circulation pressure below the threshold needed to close the pressure switch contacts during the wash phase. The condenser should be tested and replaced if it shows loss of capacitance.

  4. 04

    Loose or corroded wash motor starter connections

    Wiring / connection

    Poor electrical connections at the wash motor primary or auxiliary starter terminals can cause intermittent or complete loss of motor operation. Inspect the terminal connections for corrosion, looseness, or burn marks and reseat or clean them as needed.

  5. 05

    Wash motor failure

    Part replacement

    If the motor condenser and connections check out correctly but the motor still does not circulate water, the wash motor itself may have failed internally. This would prevent any pressure buildup in the system and would persistently trigger AL 05 regardless of filter condition.

See the test procedure for each cause

Frequently asked questions about AL 05

What does AL 05 mean on a Ariston dishwasher?
AL 05 is a clogged filters alarm indicating that the pressure switch contacts did not close after the water fill and filter cleaning cycle completed. The dishwasher expects to detect adequate water pressure through the filtration system, and when that pressure is not confirmed, it shuts down and displays AL 05. The fault can also be caused by wash motor circuit problems, including failed starter connections or a faulty motor condenser, rather than an actual filter blockage.
How do I fix the AL 05 error on my Ariston dishwasher?
Start by removing and thoroughly cleaning the mesh plate, main filter, and microfilter located at the bottom of the dishwasher tub. Rinse them under running water and clear any debris before reinstalling them. If the error returns after cleaning, the next steps are to inspect the wash motor starter connections for corrosion or looseness and to test the motor run capacitor and pressure switch for correct operation.
Is it safe to use my Ariston dishwasher while the AL 05 code is displayed?
No, you should not continue running the dishwasher while AL 05 is active. The machine has halted its cycle because it cannot confirm proper water circulation, which means dishes will not be cleaned effectively and continued operation could put unnecessary stress on the wash motor or other components. Resolve the underlying cause before running another cycle.
Will resetting my Ariston dishwasher clear the AL 05 error?
A reset may temporarily clear the display, but AL 05 will return on the next cycle if the root cause has not been fixed. The fault is triggered by a condition the control board actively monitors during every wash cycle, so simply resetting without cleaning the filters or addressing a motor circuit fault will not resolve the problem.
How much does it cost to repair an AL 05 error on an Ariston dishwasher?
If the fix is simply cleaning the filters, there is no parts cost involved. If a component needs replacement, a new pressure switch typically falls in the range of $15 to $50, a replacement motor run capacitor generally costs $10 to $30, and a replacement wash motor can range from $80 to $200 or more depending on the model. Labor costs for a technician will vary by region and the complexity of the repair.

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