Bosch · Dryer
Bosch Dryer E18 Error Code
Condensate pump or drain path blocked
What this error means
E18 signals condensate removal failure—water from the heat exchanger cannot exit through the drain hose or internal pump. Distinct from E03 kink faults, E18 often means a clog or failed pump on plumbed heat-pump dryers.
How E18 is detected
When E18 appears on a Bosch dryer, the control board has confirmed that water did not leave the machine within the programmed drain window. On Bosch WQB245B0UC, Bosch WQB245AXUC, and similar variants, the drain pump runs for a fixed interval—often three to seven minutes on washers and dishwashers—while a pressure switch or turbidity sensor verifies the tub or sump is empty. If water remains, the cycle stops to prevent spin with a full tub or overflow on the next fill.
Most E18 calls are resolved without parts: unplug and disconnect the drain hose at both ends—flush with warm water. Restricted drain paths mimic pump failure because the impeller spins against a blocked hose or filter. Document whether the pump hums audibly during the drain step; a humming pump with no water movement points to a clogged filter or kinked hose, while silence may indicate a failed pump motor or loose wiring at the harness.
After clearing blockages, run a short cycle and listen at the drain hose for steady water flow. If E18 returns on the next load with a clean filter and straight hose, measure resistance at the pump motor connector per the service manual for your model before ordering a replacement pump assembly.
Common causes
- Sludge clog in the condensate drain hose
- Pump impeller blocked by lint entering the drain circuit
- Standpipe blocked at the wall connection
- Failed condensate pump motor on auto-drain models
Step-by-step fixes
- 1Unplug and disconnect the drain hose at both ends—flush with warm water
- 2Check the pump access area per your manual for debris in the impeller
- 3Verify the standpipe accepts water from a bucket pour test
- 4Run a timed cycle and listen for pump operation in the first ten minutes
When to call a technician
E18 with a clear hose and active standpipe usually requires condensate pump replacement inside the cabinet.
Affected models
- Bosch WQB245B0UC
- Bosch WQB245AXUC
- Bosch WTG865H4UC
Prevention & maintenance
- Clean drain filters and hose terminations monthly on high-use dryers to prevent E18 from lint and food debris buildup.
- Record when E18 appears in the cycle and whether it clears after a 60-second power reset on your Bosch dryer—that detail speeds diagnosis if you call service.
- Keep the model and serial number from the rating plate when ordering parts for E18; Bosch uses multiple revisions with different harness lengths and board firmware.
- Photograph wiring connector orientation before disconnecting any component while troubleshooting E18; reversed plugs on pumps and valves cause immediate repeat faults.