Convotherm Combi Oven Error Code E27.0: Thermal Cutout Reads Too Hot
E27.0 on the older Convotherm OES, OEB, OGS and OGB ovens means the thermal cutout (B8) is reading too high a temperature. The manual's only response is to contact customer service. Let the oven cool and keep it off until a technician finds the reason.
High: a safety device is reporting overheating and the oven stops until the cause is found.
- Code
- E27.0
- Maker
- Convotherm
- Equipment
- Combi ovens
- Applies to
- Convotherm OES / OEB / OGS / OGB (older, pre-C4)
What does Convotherm error code E27.0 mean?
The thermal cutout B8 is the oven's overheating safety device, and the control reads it as a temperature signal. When the reading goes above the limit, the control assumes the oven is overheating and stops heating at once, showing E27.0. The reading may be true, for instance if a heating relay is stuck closed or a fan has stopped moving air, or it may come from a cutout or wire that reads wrongly. The control cannot tell which, so it treats every case as a real overheat. The manual gives no operator step other than to contact customer service. This is a safety message and the cause has to be found before the oven is used again. What an operator can do is let the oven cool, make sure the air intake is clear, and tell the technician what was running.
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
- E27.0 on the display
- Heating stops
- Oven chamber or cabinet very hot
- Cooling fans running hard
Possible causes
Likely causes — what usually sits behind error code E27.0 on this control. A technician confirms which one it is before any part is replaced.
- Heating relay or gas valve staying on when it should switch off
- Cooling air blocked by a clogged filter or intake
- Chamber fan stopped, so heat builds up
- Cutout or its wiring reading falsely high
Safe checks before calling for service
- Switch the oven off and let it cool without opening the door wide.
- Check that the fluff filter and the air intake in the base are not blocked.
- Do not restart the oven repeatedly; one restart after it has cooled is enough to see if the code returns.
- Contact customer service as the manual instructs.
- Write down the temperature setting, the mode and how long the oven had been running.
How a technician diagnoses error code E27.0
- Read E27.0 and the history, and look for fan or sensor codes that came before it.
- Compare the cutout reading with an independent thermometer in the chamber.
- Check that heating relays or the gas valve de-energize when the oven reaches the set value.
- Check the chamber fan and the cooling airflow.
- Check the B8 wiring and plug.
- Replace the part that fails its test, never the cutout alone without a cause.
- A real overheat can damage the oven and is a fire risk, so the cause has to be found with the oven off and cool.
- Relays and gas valves are tested at line voltage or gas pressure.
- A cutout that reads high may be right, so replacing it without proof could hide a real hazard.
How error code E27.0 differs from similar codes
E26.0 and E26.1 report the cutout circuit open or with a ground fault, while E27.0 reports its temperature reading.
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
Is E27.0 a real overheat?
It might be. The control treats it as one until a technician proves otherwise.
Can I run the oven at a lower setting?
No. The oven stops heating, and it should stay off until the cause is found.
Is E27.0 the same as E11.0?
No. E11.0 is the oven sensor reading too high, while E27.0 is the safety cutout.
Need help with Convotherm error code E27.0?
A technician confirms the cause on site and gives you the price in writing before any work starts.