Alto-Shaam CT Express Combi Error Code E26: N8 Safety Probe Open
E26 N8 Immersion Element Safety Probe Fault means the N8 safety probe reads open. A technician should check the N8 connection at the relay board and the N8 probe.
High: the safety probe reads open, so the immersion element is unprotected and steam cooking should stop.
- Code
- E26
- Maker
- Alto-Shaam
- Equipment
- Combi ovens
- Applies to
- Combitherm CT Express / ESi / CCi (older 4-10 and 4.10 units; boiler or generator electric/gas)
What does Alto-Shaam error code E26 mean?
On the CT Express, the steam boiler is heated by an immersion element, and a safety probe, N8, watches that element. The control reads N8 as a temperature signal. If the probe reads open, the control cannot tell how hot the element is, and it posts E26 N8 Immersion Element Safety Probe Fault. The manual lists two causes: a defective N8 connection at the relay board, or a defective N8 probe. The first is a wiring and connector matter; the second is the probe itself. The manual's action is for a technician only. This number belongs to the CT Express manual. On CT PROformance and CT Classic ovens, E26 is a different message, about sensing point 1 of the multipoint core probe, so the two should not be mixed up. Without N8 the control loses its protection for the element, so steam cooking should wait for the repair.
Affected models and control systems
Combitherm CT Express: 4-10ESi, 4-10ESiVH, 4-10CCi, CTX4-10E, CTX4-10EC and CTX4-10EVH. On CT PROformance and CT Classic ovens the same number means something else.
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
- E26 N8 Immersion Element Safety Probe Fault on the display
- Steam programs not starting
- Boiler heating stopped
Possible causes
Listed in Alto-Shaam's documentation
- Defective N8 connection at the relay board
- Defective N8 probe
Other likely causes — what usually sits behind error code E26 on this control. A technician confirms which one it is before any part is replaced.
- A connector at the relay board loosened by vibration
- Scale around the immersion element affecting the probe mount
Safe checks before calling for service
- Note the exact message and which program was running.
- Turn the oven off and let it cool.
- Avoid steam programs until the oven is checked.
- Tell the technician if E27 or other messages appeared with it.
How a technician diagnoses error code E26
- Read the code and check history for E27.
- Inspect the N8 connector at the relay board.
- Measure N8 resistance against its chart with the oven cool.
- Check the probe wiring for breaks.
- Replace N8 or repair the connector depending on the result.
- N8 protects the element, which is a high-current heating device.
- Connector and probe tests involve live control wiring.
- Operating the boiler without its safety probe is unsafe.
How error code E26 differs from similar codes
E27 on the CT Express reports the immersion element too hot, which also involves N8; on PROformance and Classic ovens E26 and E27 are core probe messages.
Technical reference
- Maker documentation
- Alto-Shaam owner support
- Edition
- MN-36008 (Rev. 9) 03/16
- Models / control
- Combitherm CT Express / ESi / CCi (older 4-10 and 4.10 units; boiler or generator electric/gas)
- Section
- Section C, Error Codes, pp. C-3 to C-8
- 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
Is this the same as E26 on a CT Classic?
No. On that oven E26 is a core probe sensing point message.
Does E26 mean the boiler is hot?
No, it means N8 reads open.
Can I use steam?
Not until the probe is repaired.
Need help with Alto-Shaam error code E26?
A technician confirms the cause on site and gives you the price in writing before any work starts.