The short answer
Water left in the bottom of the Cove DW dishwasher family splits cleanly into two cases. If the machine never drained from the day it was installed, suspect the install — the knockout plug and the hose loop. If it drained fine for years and stopped, suspect the filter, the sump and the pump, in that order.
What you see on the DW family
- Standing water in the bottom of the tub at the end of a cycle — The defining symptom. A small film of water in the sump is normal; water above the filter is not.
- The machine hums at the drain step but nothing moves — The pump is being asked to run and is either jammed or pushing against a blockage. That sound is useful and worth listening for.
- Dirty water backs up into the sink when the dishwasher drains — The shared path with the disposal or the standpipe is restricted. That is plumbing rather than appliance.
- It drains, but very slowly, and food is left on the dishes — A partial restriction. It shows up as a cleaning complaint first and a drainage complaint later.
Causes, most likely first on the DW family
- Drain hose kinked, sagging or missing its high loop — Ranked first on the DW family — where the machine has been moved or a cabinet has been refitted this is the change that caused the fault, and it needs no parts. The hose has to rise above the tub level before it falls to the drain, or the machine siphons and the line stays wet. A hose crushed behind the machine when it was pushed back does the same thing.
- Disposal knockout plug or a blocked air gap — Second — it explains a machine that never worked far better than one that stopped. A new disposal ships with a solid plug in its dishwasher inlet. If it is not driven out the hose is connected to a closed port.
- Filter and sump blocked with debris — Third — it is the cheapest thing in the chain and often the whole answer. Labels, seeds, bones and glass collect in the sump and blind the filter. Once the filter is loaded, the pump cannot pull through it, and the machine reports a drain fault it does not really have.
- Drain pump jammed or failed — Fourth — because everything above it is free and this one is not. The hum-versus-silence distinction tells you which it is. A chip of glass or a fruit stone wedges the impeller, and the motor hums without turning. A pump that has actually failed is silent at the drain step instead.
- Body: The order below follows the shared parts rather than the differences — the stems in the DW family carry the same running gear and diverge at the cabinet — which is why the top of this list is not where the brand-generic article puts it.
Check in this order, and why
- 1. Bail the standing water out first — A cup and a sponge. Nothing below can be checked through several inches of dirty water, and it also tells you how much there is.
- 2. Pull the filter stack and clear the sump by hand — Gloved, with the machine idle. On these models this is the single most productive step in the sequence.
- 3. Check the air gap or the disposal inlet — Pop the air-gap cover and clear it. On a recent disposal install, confirm the knockout plug was actually removed.
- Body: The stems in the DW family share their layout, so the order below holds across the table; where a stem differs it differs at the cabinet, not at the part you are reaching for.
Before you open anything
Safety
Isolate the machine at the breaker before you go anywhere near the pump or the lower access panel, and shut the water supply valve under the sink while you are in that cabinet. Bail the tub before reaching in — glass chips sit in the sump and are invisible under dirty water. Never run the disposal while your hand is at the dishwasher inlet.
Models in the DW family
Reference| Model number | Family key |
|---|---|
| DW2450 | cove:dishwasher:dw |
| DW2450WS | cove:dishwasher:dw |
| DW2451 | cove:dishwasher:dw |
| DW2451/ADA | cove:dishwasher:dw |
| DW2451/WS | cove:dishwasher:dw |
| DW2451ADA | cove:dishwasher:dw |
| DW2451ADA/WS | cove:dishwasher:dw |
When to call a technician
Call when the filter and sump are clean, the hose runs without a kink and rises before it falls, the air gap is clear, and the machine still hums without moving water. That puts the fault at the pump or the check valve behind the lower panel, which needs the machine isolated and pulled on these models.
Other DW dishwasher pages
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
