In short
Most drain complaints on the WAW line are cleared with a tray, a towel and ten minutes at the filter door. The point of the ranking below is to stop owners buying a pump for a fault that a coin caused.
What owners of these models report
- A bad smell from the drum between washes — Standing water and trapped debris in the filter housing. It usually accompanies a partial blockage rather than a total one.
- The drum drains but the clothes stay soaked — That is a spin problem rather than a drain problem, and it points at balance or the motor.
- The cycle ends with water standing in the drum — The drain gate was never satisfied, so the programme stopped rather than continuing over water.
- The door will not open after the cycle — Correct behaviour rather than a second fault: the lock holds while there is water above the door line.
- NEAR MISS - a small amount of water always left in the seal — Normal on a front-loading machine; the door seal holds a little water by design.
What it usually turns out to be
- Pump wiring or control fault — Last, because everything above produces the same standing water for far less money and because this one needs a meter to confirm.
- Drain hose kinked behind the machine — Common after a move or a floor clean, and it produces a slow drain before it produces no drain at all.
- Drain filter blocked — First on this family by a wide margin and by design: the filter is placed to catch debris before the pump, so that is where the debris is.
- Coin, clip or button jamming the pump impeller — Second, and often found in the same look as the first: anything small enough to pass the filter seat ends up on the impeller.
What to check first, second, third
- Run a short programme and watch when the drain is attempted — Confirms whether the cycle reaches the drain step at all, which rules the upstream stall in or out.
- Turn the pump impeller by hand once the filter is out — A jammed impeller is obvious to a finger and invisible to a meter, and this is the moment to feel for it.
- Check the filter housing for a build-up of detergent scum — A partial restriction that builds over months and that explains a slow drain with no obvious object in it.
- Put a tray and towels down and open the drain filter — It is the first thing in the water's path and the designed access point, so it is both the test and, usually, the repair.
Before you open anything
Safety
Disconnect power and close the inlet taps before starting. A machine that has stopped mid-cycle may still be holding a tub full of water, and that water leaves through the drain filter whether you are ready for it or not.
Models in the WAW family
Reference| Model number | Family key |
|---|---|
| WAW28420AU | bosch:washer:waw |
| WAW28440AU | bosch:washer:waw |
| WAW285H1UC | bosch:washer:waw |
| WAW285H2UC | bosch:washer:waw |
| WAW28620AU | bosch:washer:waw |
| WAW28640AU | bosch:washer:waw |
| WAW28790AU | bosch:washer:waw |
When to call a technician
Book a visit when the same fault returns after a correct repair. A repeat failure on these machines usually means a second fault upstream, and chasing it from the outside costs more weekends than it saves.
Other pages for this family
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
