Alto-Shaam Combi Oven Error Code E25: B3 Condenser Probe Failure
E25 B3 Condensor Probe Fault means the condenser water probe, B3, is defective or disconnected. Press the Start icon to acknowledge it, and have a technician check B3 and its wiring.
Medium: steam venting is affected until the probe is repaired.
- Code
- E25
- Maker
- Alto-Shaam
- Equipment
- Combi ovens
- Applies to
- Combitherm CT PROformance (CTP) and CT Classic (CTC); Combitherm CT Express / ESi / CCi (older 4-10 and 4.10 units; boiler or generator electric/gas)
What does Alto-Shaam error code E25 mean?
Probe B3 reads the temperature of the water in the oven's condenser, the part that cools steam before it goes to the drain. The control compares that value with the limit behind E15 and uses it to open cooling valve Y2. Before relying on the number, the control checks that the probe is present and reading within a believable range. If it is not, the control posts E25 B3 Condensor Probe Fault, using the manual's spelling. The manual lists two causes: the B3 probe has failed or it is miswired. The code does not tell you that the condenser is too hot or that cooling water is missing; it tells you the oven cannot read the condenser temperature. Pressing Start acknowledges the message and the oven then tries to return to normal operation, but the sensor circuit is still bad. E40 is a related message for the same probe when it is shorted to ground.
Affected models and control systems
CTP and CTC combis of all six sizes, 6-10 to 20-20, electric and gas. The CT Express manual includes E25 as well.
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
- E25 B3 Condensor Probe Fault on the display
- Condenser cooling not behaving normally
- Steam venting through the drain hotter than usual
Possible causes
Listed in Alto-Shaam's documentation
- B3 probe malfunction
- B3 probe miswired
Other likely causes — what usually sits behind error code E25 on this control. A technician confirms which one it is before any part is replaced.
- A pinched B3 lead near the condenser housing from earlier service
- Water leakage at the probe fitting corroding the connection
Safe checks before calling for service
- Press the Start icon once to acknowledge E25.
- Check the drain for unusually hot water or steam after a steam program.
- Do not remove panels or the condenser cover.
- If E25 returns, mention any plumbing or service work done near the oven's water inlet.
How a technician diagnoses error code E25
- Read the code and check for E15 or E40 in the history.
- Inspect B3 and its connector with the oven cool.
- Compare the wiring against the diagram, since the manual lists a miswired probe.
- Measure the B3 resistance and compare with the chart.
- Replace the probe once measurement confirms it has failed.
- B3 is in the condenser water path where leaks and live wiring are close together.
- A shorted probe (E40) and an open or miswired one (E25) have to be separated with a meter.
- If cooling cannot be verified, steam venting could overheat the drain.
How error code E25 differs from similar codes
E40 reports probe B3 shorted to ground; E25 covers B3 being defective, miswired or disconnected, and E15 is high water temperature at B3.
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); Combitherm CT Express / ESi / CCi (older 4-10 and 4.10 units; boiler or generator electric/gas)
- 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
Why do E25 and E40 both name B3?
E40 means shorted to ground; E25 is the broader defective or disconnected message.
Does E25 mean the condenser is hot?
No. It means the oven cannot read the condenser temperature.
Can I run steam programs?
It is best not to, since cooling control depends on this probe.
Need help with Alto-Shaam error code E25?
A technician confirms the cause on site and gives you the price in writing before any work starts.