Alto-Shaam Combi Oven Error Codes E289/E290: Unknown VFD Error
E289 and E290 mean a fan drive sent an error the control does not recognize: E289 for the table-top or upper drive and E290 for the lower drive. Press the Start icon to acknowledge, and suspect the drive.
High: a drive is sending messages the control cannot read and the fan may not run.
- Code
- E289 / E290
- Maker
- Alto-Shaam
- Equipment
- Combi ovens
- Applies to
- Combitherm CT PROformance (CTP) and CT Classic (CTC)
What does Alto-Shaam error code E289 / E290 mean?
The control board expects specific error numbers from each variable frequency drive, or VFD, such as under voltage or over current. If the drive sends a number the control has no meaning for, the control shows E289 Unknown Error from VFD / E290 Unknown Error from Lower VFD, depending on which drive sent it. E289 is the table-top or upper drive; E290 is the lower drive on roll-in ovens. The manual lists a possible VFD malfunction, and for E290 a possible lower VFD malfunction. A drive that sends an unrecognized message is probably confused itself, perhaps because its software is damaged or its signals are corrupted. Pressing Start acknowledges the message and the oven then tries to return to normal operation, but if the drive keeps sending messages the control cannot read, the fan cannot run properly. Because the control gives no more detail, the drive's LED blink code is the next place to look.
Affected models and control systems
Electric and gas CTP and CTC ovens, 6-10 to 20-20. E289 is the table-top or upper drive and E290 is the lower drive of a roll-in.
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
- E289 or E290 on the display
- Fan not running or running erratically
- Other VFD error codes appearing too
Possible causes
Listed in Alto-Shaam's documentation
- Possible VFD malfunction (E289)
- Possible lower VFD malfunction (E290)
Other likely causes — what usually sits behind error code E289 / E290 on this control. A technician confirms which one it is before any part is replaced.
- Electrical noise on the drive's communication line corrupting its messages
- A drive with damaged software after a power event
Safe checks before calling for service
- Press the Start icon once to acknowledge the message.
- Note which of E289 or E290 appeared.
- Turn the oven off and on once and see whether it returns.
- Tell the technician if any other VFD code appeared before it.
How a technician diagnoses error code E289 / E290
- Read the code and check history for other VFD codes.
- Read the LED blink code on the drive named.
- Check the drive wiring and CAN link.
- Check supply voltage and grounding.
- Replace the drive named when the evidence points to it.
- The drive is part of a live control circuit.
- The drive's own signals can be read only with service tools.
- A replaced drive needs matching settings.
How error code E289 / E290 differs from similar codes
E289 and E290 are catch-all messages for VFD errors the control cannot name; E210 to E228 name specific conditions.
Technical reference
- Maker documentation
- Alto-Shaam owner support
- Edition
- MN-35949 Rev 08 03/22
- Models / control
- Combitherm CT PROformance (CTP) and CT Classic (CTC)
- Section
- Error Codes, pp. 25-31
- 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 Alto-Shaam combi oven error codes
What does unknown mean?
The control received an error number it has no meaning for.
Which drive is E290?
The lower drive.
Is the drive definitely bad?
The manual says to suspect it, but wiring and supply should be checked first.
Need help with Alto-Shaam error code E289 / E290?
A technician confirms the cause on site and gives you the price in writing before any work starts.