Convotherm Combi Oven Error Code E23.1: Steam Sensor Ground Fault
E23.1 on the older Convotherm OES, OEB, OGS and OGB ovens means the steam generator sensor (B4) has a ground fault. The manual's only response is to contact customer service. Steam stays off until it is repaired.
Medium: steam is off, but dry cooking continues.
- Code
- E23.1
- Maker
- Convotherm
- Equipment
- Combi ovens
- Applies to
- Convotherm OES / OEB / OGS / OGB (older, pre-C4)
What does Convotherm error code E23.1 mean?
Sensor B4 reports the steam generator temperature, and its signal should only travel through its own circuit. A ground fault means the signal has found another path to ground. Heat and moisture around the generator can wear cable insulation or wet a connector, and then the control sees a wrong value. It cannot rely on that value to protect the generator, so it stops steam and shows E23.1. A ground path like this can come and go as the cable heats and cools, so the oven may work for a while after a restart. The manual's response is to contact customer service, because finding a damaged spot in the cable means measuring it with the oven open. Because the cable lies close to the generator, repeated heating and cooling slowly hardens the insulation until it cracks. Cleaning chemicals and condensation can then reach bare wire. Neither is visible without removing the panels, which is why the manual does not ask the operator to look for it.
Affected models and control systems
Older Convotherm combi ovens in the OES, OEB, OGS and OGB line, which came before the C4. The source is that line's English user manual, a translation of the original, with no revision number printed.
Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.
What you may notice
- E23.1 on the display
- Steam programs stop
- Message returns after the oven warms up
- Dry heat still works
- Steam output missing even though the water supply is on
Possible causes
Likely causes — what usually sits behind error code E23.1 on this control. A technician confirms which one it is before any part is replaced.
- Cable insulation worn near the hot generator
- Moisture in the sensor plug
- Sensor touching a metal bracket
- Sensor failed internally
Safe checks before calling for service
- Switch the oven off and let it cool.
- Do not use water or cleaner near the back panel while the oven is waiting for service.
- Try one restart and a dry-heat program.
- Contact customer service as the manual instructs.
- Note whether the code returns only once the oven is hot.
How a technician diagnoses error code E23.1
- Read E23.1 and the history.
- Disconnect B4 and test the sensor and cable for a path to ground.
- Inspect the cable and plug for wear and moisture.
- Check the board input.
- Replace the cable or sensor.
- Run a steam test.
- Ground paths are traced with a meter near live parts.
- Intermittent insulation damage needs the oven heated while it is tested.
- Replacing a sensor on the generator means draining it first and refilling it, so the work is plumbing as well as electrical.
How error code E23.1 differs from similar codes
E23.0 is the same sensor with an open circuit.
Technical reference
- Maker documentation
- Convotherm owner support
- Edition
- No revision/part number found in the text read
- Models / control
- Convotherm OES / OEB / OGS / OGB (older, pre-C4)
- Section
- Troubleshooting, Errors and required responses, pp. 161-162
- Checked
- October 2026
We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.
Related Convotherm combi oven error codes
Why does E23.1 come and go?
Heat can open or close a damaged insulation path, so the reading changes.
Is E23.1 dangerous?
The control stops steam to protect the generator, which is the safe response.
Why does dry heat still work?
The dry-heat functions do not use the steam generator sensor, so the control lets them continue. Steam and combi programs wait for the repair.
Need help with Convotherm error code E23.1?
A technician confirms the cause on site and gives you the price in writing before any work starts.