Convotherm Combi Oven Error Code E01.0 / E01.1: Low Water
E01.0 and E01.1 on the older Convotherm OES, OEB, OGS and OGB ovens mean the oven did not get enough water. Open the water supply first. If the code stays, contact customer service.
Medium: steam stops until water arrives, but a closed tap is a common and easy fix.
- Code
- E01.0 / E01.1
- Maker
- Convotherm
- Equipment
- Combi ovens
- Applies to
- Convotherm OES / OEB / OGS / OGB (older, pre-C4)
What does Convotherm error code E01.0 / E01.1 mean?
These older combi ovens need water to make steam, and the control waits for the right level after a steam call. On the OEB and OGB, the control reports not enough water in the steam generator. On the OES and OGS, the manual describes not enough water, with the level reached too slowly, which is to say the steam generator filling time was too long. In both cases the control starts the fill, waits for the level to be reached, and stops with the E01 message if it is not reached in time. The display shows the code, E01.0 or E01.1, and the oven blocks steam until the water arrives. The control cannot tell whether a tap is closed, a hose is pinched or a valve is stuck, which is why the manual's first line is so simple: open the water supply. A tap shut during cleaning is a typical reason a kitchen sees this the next morning.
Affected models and control systems
Convotherm OES, OEB, OGS and OGB combi ovens (the older, pre-C4 line), from that line's user manual, an English translation of the original edition. It does not state a revision number.
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
- E01.0 or E01.1 shown on the display
- Steam does not start
- Slow filling noises, or none at all
- Steam program stops after the fill time
Possible causes
Likely causes — what usually sits behind error code E01.0 / E01.1 on this control. A technician confirms which one it is before any part is replaced.
- Water tap closed after cleaning or maintenance
- Low line pressure making the steam generator fill too slowly
- Inlet filter screen blocked with scale
- Fill valve opening only partly
Safe checks before calling for service
- Open the water supply tap to the oven fully.
- Look at the supply hose behind the oven for kinks.
- Restart the oven and begin a short steam program.
- If the code returns, contact customer service as the manual directs.
- Note which of the two codes appeared, since E01.1 relates to a slow fill.
How a technician diagnoses error code E01.0 / E01.1
- Read the code and history to see whether the fill is absent or slow.
- Check the supply tap, pressure and inlet screen.
- Test the fill valve for coil voltage and flow.
- Check the level sensing of the steam generator against the control reading.
- Descale or replace parts only after the tests identify the problem.
- Fill valves and level sensors on the steam generator connect to the main board at line voltage, which an operator should not open up.
- Slow filling can be a scale problem inside the generator, which needs descaling with the right chemical.
- Gas models also carry burners, and testing the water side requires care around them.
How error code E01.0 / E01.1 differs from similar codes
On the C4, the matching code is E01.x with the same water meaning but a different manual.
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
What is the difference between E01.0 and E01.1?
The manual groups them. On OES and OGS ovens it describes a level reached too slowly, so a long fill time.
Does the oven work without steam?
Dry hot-air functions may still run, but steam and combi programs wait for water.
Is the first step really just opening the tap?
Yes, that is what the manual lists first. Contact customer service if the code stays.
Need help with Convotherm error code E01.0 / E01.1?
A technician confirms the cause on site and gives you the price in writing before any work starts.