Alto-Shaam Combi Oven Error Code E26: B10 Point 1 Probe Failure

What does Alto-Shaam error code E26 mean?

The multipoint core probe B10 carries more than one temperature sensor, and the control reads each one. When it finds the first sensing point open or shorted, it posts E26 B10 - Point 1 - Core Temperature Probe Multipoint Fault. That means the other points may still read, but the control cannot rely on a probe with a bad one. The manual lists two causes: the B10 probe has failed, or it is miswired or its wires are disconnected. Start acknowledges the message and lets the oven carry on. If the probe is simply not seated, reseating it fixes the message. If a sensing point has failed inside the probe, the message returns every time the probe is used. On CT PROformance and CT Classic ovens this number is a probe code; the CT Express manual uses E26 for a different, boiler safety message.

Affected models and control systems

The six CT PROformance and CT Classic sizes (6-10, 10-10, 7-20, 10-20, 20-10, 20-20), electric and gas. If your oven is a CT Express, E26 refers to a boiler safety probe instead.

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 Point 1 message on the display
• Core-temperature program not available
• Core probe plugged in but no reading shown

Possible causes

Listed in Alto-Shaam's documentation

• B10 probe malfunction
• B10 probe miswired or wires disconnected

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 kink or break in the probe cable close to the handle end where it is bent most
• Food residue on the plug causing a poor contact for this one point

Safe checks before calling for service

How a technician diagnoses error code E26

1. Read the code and check whether other point messages (E27 to E29) are active.
2. Inspect the probe and cable, and clean and reseat the connector.
3. Check continuity of each sensing line of B10 with a meter.
4. Verify the receptacle wiring against the diagram.
5. Replace B10 once the failed sensing line is proven.

How error code E26 differs from similar codes

E27, E28 and E29 name sensing points 2, 3 and 4 of the same probe; E22 reports the probe as a whole; on CT Express E26 is a different boiler safety message.

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.