Bosch E24 Drain Error at Square One

The call

A Square One condo, three-year-old Bosch dishwasher, showing E24 at the end of every cycle with water sitting in the bottom of the tub.

The owner had done their homework. They had found that E24 means a drain restriction, pulled the filter assembly, rinsed it, refitted it — twice — and the code came straight back. That is exactly the right first move, and the fact that it did not work told us where to look next.

We talk a lot of E24 callers through the filter clean on the phone and never book a visit, because about half of them are solved that way. This was one of the other half.

Diagnosis

The drain path on these machines runs filter → sump → drain pump → hose → standpipe or disposal. The owner had cleared the first stage. So we started at the second.

• Filter assembly: genuinely clean, correctly seated
• Sump: a small amount of debris, nothing that would restrict flow
• Drain hose: clear, correctly routed with a proper high-loop
• Drain pump impeller: jammed

The culprit was a fragment of glass roughly the size of a fingernail, wedged against the impeller blades. The pump could still turn — which is why the machine attempted to drain rather than failing outright — but it could not move water at anything like the rate the control board expects. The board timed the drain, decided it was taking too long, and threw E24.

The impeller itself had been chewed by the glass. That matters, because a damaged impeller moves water inefficiently even once the obstruction is gone.

The fix

The pump came out, the glass came out, and the impeller was inspected under light. It had visible scoring and a chipped blade edge, so it was replaced rather than cleaned and refitted. A damaged impeller would have produced the same fault again within weeks, and we would rather do it once.

We also checked the sump for further fragments — where one piece of glass has gone through, others often follow — and found two smaller pieces that would have arrived at the pump eventually.

Then a full cycle, timed. Drain completed well inside specification, no code.

Outcome

Sixty minutes, $189 before HST, and the machine has run clean since.

The honest note for anyone reading this with E24 on their own machine: try the filter first. Pull it, rinse it under a tap, refit it and run a cycle. It costs nothing and it works often enough that we tell people to do it before booking.

If the code returns after that, the pump is the next stage, and that one does need opening up. The distinction between the two matters:

• E24 — drain restricted, usually the filter, frequently a ten-minute job you can do
• E25 — drain pump blocked, needs the pump opened, ours to do

And a small piece of advice specific to glassware: a chipped wine glass that goes through the dishwasher tends to leave part of itself behind. If something breaks in the machine, it is worth checking the sump before running it again.

Covered by our 60-day parts and labour warranty. Quote job #4477 if the same fault ever returns.