The short answer for DW models
On the DW line a drainage fault has a clear order to it. Clear the filter and the sump first because they are free, then the hose and the household connection, and only then treat the pump as a suspect.
What it looks like from the outside
- A humming at the drain step with nothing moving — The pump is being asked to run against a blockage.
- Water backing up into the sink when the machine drains — The household connection, not the machine.
- Debris visible in the sump under the filter — What the filter should have caught and did not, usually because it is full.
- Water draining very slowly rather than not at all — A partial restriction, which points at the filter, the sump or a partly blocked hose.
- NEAR MISS — water on the floor rather than in the machine — That is a leak and it needs the water shut off, not a drain cleared.
Likely causes on DW, ordered
- Filter and sump packed with food waste — Ranked first because it is the commonest and the only one the owner is asked to maintain.
- Waste disposer knockout plug still in place — Second and the reason a machine that drained yesterday does not today: fitting a disposer without removing the plug seals the drain completely.
- No high loop in the drain hose — Without the loop, sink water siphons back into the machine, which reads as a drain that never worked.
- Sink waste trap blocked — The machine drains into it, so a blocked trap stops the machine as surely as a blocked hose.
What to look at first, second, third
- Before anything else — On DW models, four of the four causes above are checkable without a panel coming off, and this order puts every one of them before anything that is not.
- Fill the sink and let it drain — A sink that drains slowly means the household waste is the problem, not the machine.
- Check the air gap on the worktop if the installation has one — Grease builds inside it and it is the one part of the path visible from above.
- Look into the sump with a torch for debris and foreign objects — Glass and fruit stones reach the impeller once the filter stops catching them.
Before you open anything on this machine
Safety
Switch off at the breaker or unplug, then close the water supply valve. A capacitor can hold a charge after the power is off. On a dishwasher the sharpest hazard is glass: broken fragments collect in the sump under the filter and they are invisible in standing water, so wear a glove and use a torch rather than feeling around.
Models in the DW family
Reference| Model number | Family key |
|---|---|
| DW1831D0WE | avanti:dishwasher:dw |
| DW1832D1BE | avanti:dishwasher:dw |
| DW1833D3SE | avanti:dishwasher:dw |
| DW18D0WE | avanti:dishwasher:dw |
| DW18D1BE | avanti:dishwasher:dw |
| DW18D3SE | avanti:dishwasher:dw |
| DW21UT22N224 | avanti:dishwasher:dw |
When to call a technician
Call when the filter, the sump, the hose and the household waste are all proved clear and the machine still will not drain, or when the fault needs the sump cover or the pump disturbed. That is the point where water and live terminals share a space and it stops being owner work.
Other DW problems we cover
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
