Merrychef High-Speed Oven Error Code E104: Overheat Stats Released
E104 means the 12 VDC safety thermostat circuit is open. One of the cavity overheat thermostat, the magnetron overheat thermostats or the convection fan's internal protection has opened. Switch the oven off and on; if it persists, remove it from mains power for 20 minutes and have the safety wiring checked.
High: the safety circuit has opened and the oven will not heat until it is cool and the cause is fixed.
- Code
- E104
- Maker
- Merrychef
- Equipment
- High-speed ovens
- Applies to
- All Merrychef eikon speed ovens (e2s, e3, e4, e4s, e5, e6)
What does Merrychef error code E104 mean?
A string of safety thermostats is wired in series on a 12 VDC circuit. Normally the circuit is complete. If the cavity thermostat, a magnetron thermostat or the convection fan's built-in protection opens because of heat, the circuit breaks and the oven records E104: OVERHEAT STATS RELEASED. The manual's first step is to switch the oven off and on again. If the code persists, remove the oven from mains power for 20 minutes to let it cool and then check the safety wiring and its continuity. The cavity thermostat has a reset button on the back panel. The error stays until the board temperatures drop below 50 C. The manual lists a dirty front filter, lack of cooling, and mains being disconnected before the cavity had cooled as causes. Cleaning the magnetron fins and the front filter is part of the remedy.
Affected models and control systems
Merrychef eikon e2s with the QTS touch screen and SRB relay board controller. Confirmed in the e2s service manual.
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
- E104 OVERHEAT STATS RELEASED on the display
- Oven refuses to heat until it has cooled
- Oven fails again soon after a restart
Possible causes
Listed in Merrychef's documentation
- Dirty front filter
- Lack of cooling
- Mains disconnected before the cavity had cooled
Other likely causes — what usually sits behind error code E104 on this control. A technician confirms which one it is before any part is replaced.
- Magnetron cooling fins packed with grease or dust
- Convection fan protection tripping because the fan is struggling
- A thermostat that opens too early after repeated overheating
Safe checks before calling for service
- Let the oven stand with the power off for at least 20 minutes.
- Clean the front air filter and check that the vents are clear.
- Switch the oven on again and see if the code clears.
- Do not unplug a hot oven right after a long cook; let it cool down first, and note when E104 appeared.
How a technician diagnoses error code E104
- Read the log for E104, board temperatures and cook times before the event.
- Check the cavity thermostat and press its reset at the back panel.
- Test continuity through the series safety circuit to find the open device.
- Clean the magnetron fins and the filter, and inspect the convection fan.
- Replace the thermostat that fails the test.
- The safety circuit passes through the cabinet near mains and high-voltage parts.
- Finding which of several series thermostats opened takes continuity testing with the oven isolated.
How error code E104 differs from similar codes
E104 is the safety thermostat circuit opening; E103 is the ambient board temperature reading above 70 C, and E117 was the old-firmware overheat message.
Technical reference
- Maker documentation
- Merrychef owner support
- Edition
- Feb 2021/v1; 50Hz & 60Hz, English
- Models / control
- All Merrychef eikon speed ovens (e2s, e3, e4, e4s, e5, e6)
- Section
- Section 5 Service information, Error codes & fault finding tips
- 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 Merrychef high-speed oven error codes
How long should I wait before restarting?
The manual says to remove the oven from mains for 20 minutes if switching off and on does not clear it.
Why does the code stay after the oven cools?
The error stays until the board temperatures drop below 50 C.
What if the code keeps returning?
Repeated trips point to poor cooling or a failing thermostat, and need a technician.
Need help with Merrychef error code E104?
A technician confirms the cause on site and gives you the price in writing before any work starts.