Alto-Shaam Combi Oven Error Code E29: B10 Point 4 Probe Failure

What does Alto-Shaam error code E29 mean?

The multipoint core probe, B10, lets a cooking program follow the temperature at several depths in the product. The control scans each sensing point and expects a signal in a believable range. When point 4 reads open, shorted or missing, the control posts E29 B10 - Point 4 - Core Temperature Probe Multipoint Fault. The manual gives two causes: the B10 probe has failed, or it is miswired or its wires are disconnected. Since this is the fourth point, it is the last one in the series that the manual lists for B10. If only E29 appears, a single line inside the probe is the best suspect. If E26 to E28 appear with it, the plug, the cable or the oven receptacle becomes more likely. Pressing Start acknowledges the message and the oven then tries to return to normal operation, but cooking by core temperature will retest the probe.

Affected models and control systems

Alto-Shaam Combitherm CT PROformance and CT Classic combi ovens in sizes 6-10, 10-10, 7-20, 10-20, 20-10 and 20-20, electric and gas, with the multipoint core probe option. These numbers are separate from the CT Express message list.

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

• E29 Point 4 message on the display
• Multipoint probe program not available
• Probe in the food but its last reading missing

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 E29 on this control. A technician confirms which one it is before any part is replaced.

• A pin inside the probe plug bent so it no longer touches its contact
• A cable crushed by the door gasket, damaging one wire only

Safe checks before calling for service

How a technician diagnoses error code E29

1. Read the code and check for E26, E27 and E28 in the history.
2. Inspect the probe plug, pins and cable.
3. Check the continuity of the fourth sensing line from plug to tip with a meter.
4. Check the oven receptacle and its wiring to the control board.
5. Replace B10 when one line is confirmed open, and not before.

How error code E29 differs from similar codes

E29 is the fourth of the B10 point messages, after E26, E27 and E28; E45 to E48 report the same probe shorted to ground.

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.