Why Is My Asko Dishwasher Not Draining?

When an Asko dishwasher is not draining but the motor still hums, the drain pump is the first thing to suspect. On this call the pump had broken apart inside its housing, so the motor ran without moving any water. I installed a new 120V 60Hz drain pump, part number 467997, and the machine drained normally again.

What does it mean when the dishwasher hums but the water stays in the tub?

It means something is drawing power and trying to run, but nothing is moving the water out. In a dishwasher the drain pump is a small motor with an impeller on the end of its shaft. The motor is what hums. If the impeller is blocked by a piece of glass or a fruit pit, the motor strains against it and you get the same sound. If the impeller has separated from the shaft or the plastic housing inside has cracked up, the motor spins freely and still moves nothing. Either way you open the door at the end of the cycle and find standing water in the bottom.

A humming sound narrows it down a lot. A pump that is electrically dead makes no noise at all, which usually points at the control board or the wiring to the pump instead.

How the repair went on this Asko

The machine was an Asko dishwasher, model 107325141, at a house in Irvine. The drain pump sits at the bottom of the tub under the sump, so it comes out from below once the unit is loose. When I had the old pump in hand, the internals had come apart, which explains a motor that runs and a tub that stays full. The replacement went in the same way it came out, and the dishwasher pumped the water out on the test cycle.

What can you check yourself?

Start with the things you can reach from inside the tub with the door open and the machine off. Pull the bottom rack, lift the filter assembly out, and look for food, labels off jars, or glass in the sump. A toothpick stuck across the pump inlet will stop drainage completely and costs nothing to fix.

After that, check the drain hose where it meets the sink. If the dishwasher drains into a garbage disposal that was recently installed, the knockout plug inside the disposal inlet may never have been removed, and the water has nowhere to go. An air gap on the counter can also pack full of debris.

Past the filter and the sump, the work moves into the pump itself and its wiring, and that is my side of the job. The pump runs on line voltage and the machine needs to be disconnected from power before anything under the tub comes apart.

Is a drain pump worth replacing?

On most dishwashers, yes. The pump is a single assembly, it is a part that is designed to come out, and the rest of the machine is usually untouched by the failure. The judgment changes when the pump failure comes with a leaking tub seam or a dead control board on an older unit, because then you are stacking repairs on a machine that has other problems coming.

FAQ

Why is my Asko dishwasher not draining even after I cleaned the filter?
Because the blockage or the fault is past the filter. Common spots are the check valve that keeps drain water from flowing back into the tub, the drain hose where it loops up under the sink, and the pump impeller itself. A hose that has been crushed behind the machine during an install will also hold water in the tub even with a perfectly clean filter and a healthy pump.

Can I keep using a dishwasher that will not drain?
No. The wash arms pull from the water sitting in the sump, so every cycle recirculates dirty water over the dishes and they come out worse than they went in. If the pump is jammed, running it repeatedly also keeps heating a stalled motor winding. Bail the water out with a cup and a sponge and leave the machine off until the drain problem is sorted.

How long does a dishwasher drain pump last?
Usually many years, since it only runs for a minute or two per cycle. What shortens its life is what goes through it. Broken glass is the worst offender, because the shards chip the impeller vanes and score the housing. Scraping plates before loading and checking the sump every few months for hard debris does more for pump life than anything else.

We repair dishwashers throughout Irvine and the surrounding Orange County cities. You can book a visit online or reach Cactus Appliance at (949) 544-5550.