Bosch Dryer Error Code E03: Condensate Drain Hose Blocked or Kinked
What the code means
Bosch's US dryer error code guide lists E03 as "The condensation drainage hose is blocked or kinked", and Bosch's own E03 support page gives the same meaning with three steps: loosen the hose clip at the siphon (the drain connection), carefully remove the drainage hose, and clean the hose and the siphon spigot, making sure the hose is installed without kinks. Condenser and heat pump dryers collect the moisture from the laundry as water. If your dryer is set up to send that water straight down a drain, the pump pushes it through this hose, and when it can't get through the dryer stops and shows E03. It isn't the same as E01 or E02 (Bosch lists E01/E02 as a blocked lint filter, and E02 on some models as a control board relay fault) or the electronic faults like E90. A Bosch training manual for the older WTMC/WTXD dryers, as quoted by the repair site MyPros+, uses E:03 for a different thing: maximum drying time of 240 minutes exceeded during normal use. If your dryer has no drain hose, read it that way and look at airflow, lint and venting instead.
Likely causes
- The condensate drain hose is kinked, crushed behind the dryer or pulled into a tight bend, which is the first thing Bosch says to check
- Lint or residue blocking the drain hose or the siphon spigot it connects to, which is why Bosch says to clean both
- A blocked sink trap or standpipe where the hose drains, so water backs up (general plumbing background)
- On older WTMC/WTXD models only: the 240-minute maximum drying time was reached, usually from a blocked lint filter, vent or condenser or an overloaded drum (per the training manual quoted by MyPros+)
Safe DIY checks
Unplug the appliance or switch off its breaker before opening panels.
- Turn the dryer off and unplug it before you move it or touch the hose.
- Pull the dryer out carefully and follow the thin drain hose from the back to the drain. Straighten any kinks or sharp bends and make sure nothing is pressing on it.
- Loosen the hose clip where it connects to the siphon or drain, ease the hose off, and flush it through with warm water. Clean out the spigot it pushes onto as well.
- Check the sink trap or standpipe the hose drains into isn't clogged, then refit the hose and tighten the clip.
- Empty the water container and clean the lint filter while you're there, then plug back in and run a short program. If E03 clears and stays gone, you're done.
- If your dryer has no drain hose, treat E03 as a long drying time warning: clean the lint filter and condenser or heat exchanger, check any vent hose, and don't overload the drum.
🛠 When to call a pro
- E03 comes back with a clear, straight hose and a free-flowing drain: the condensate pump or its sensing may need testing. Call Bosch at 1-800-944-2904 or a qualified technician.
- You see water under the dryer or the water container fills even though the hose is connected.
- The dryer is under warranty: use Bosch's own service so the repair stays covered.
Parts that commonly fix it
Always match the part number to your exact model.
Condensate drain hose
Replace a split, crushed or permanently kinked hose. Match it to the E-Nr on your dryer's rating label.
Search eBay →Multimeter
What a technician uses to test the condensate pump if the hose and drain are clear.
Search eBay →Sources
- Bosch US: Dryer Error Codes guide (E03: the condensation drainage hose is blocked or kinked; E01/E02 lint filter, E90 group electronic faults; 1-800-944-2904)
- Bosch: Dryer Error Code E03 support page (condensation drainage hose blocked or kinked; loosen hose clip on the siphon, remove hose, clean hose and siphon spigot)
- MyPros+: Bosch Dryer Error Code E:03, quoting the Bosch WTMC/WTXD dryer training manual p. 64 (maximum drying time exceeded after 240 minutes on older models)
Last reviewed 2026-10-25. Always confirm against the manual for your exact model number.