Verified from the manual · Updated October 2026
Alto-Shaam steam oven error codes
31 codes for Combitherm CT PROformance series (including Prodigi 7-20 Pro) commercial combi ovens, transcribed from the official documentation with page references.
Commercial ovens log codes to an error history. Press Start to acknowledge; the oven then tries to resume. Codes marked service need an Alto-Shaam authorized service provider.
| Code | What it means | Likely cause | What to do | Service? |
|---|---|---|---|---|
| E01 | Low water in steam generator (roll-in models). | Water supply shut off or low pressure; calcium on the water-level probe; fill solenoid, drain pump or drain cap faults. | Check the water supply and pressure and descale the generator; otherwise service. | Call service |
| E02 | Control (relay board) temperature above 176°F / 80°C. | Cooling fan malfunction or blocked air intake. | Clear the air intake; service if the fan has failed. | Call service |
| E03 | Fan motor error (table-top / upper motor). | Motor or fan wheel locked, or the Hall-effect sensor does not detect rotation. | Service. | Call service |
| E04 | Lower fan motor error (roll-in models). | Lower convection fan does not spin within 60 seconds. | Service. | Call service |
| E05 / E06 | VFD communication failure (upper / lower). | Loss of power to the VFD, CAN cable disconnected, VFD or control board fault. | Service. | Call service |
| E07 / E08 | Error reported by the VFD (upper / lower). | See the VFD error list and match the number of green-LED blinks. | Service. | Call service |
| E11 | Convection temperature high (cavity above 600°F / 315°C for 25 s). | Convection element contactor locked on, or cavity probe N6 malfunction. | Service. | Call service |
| E13 | Steam generator temperature high (above 248°F / 120°C for 25 s). | Calcium on the water-level probe or in the generator; steam element contactor locked on; probe B4 fault. | Descale; service if it persists. | Call service |
| E15 | Condenser temperature high (above 212°F / 100°C). | Water supply shut off, plugged steam bypass hose, or cooling-water solenoid Y2 fault. | Check the water supply; service if it persists. | Call service |
| E20 | Single-point core temperature probe fault. | Probe not inserted into food correctly, not connected, dirty receptacle pins, or a failed probe. | Re-seat the probe and clean the receptacle pins; replace the probe if it persists. | Owner fix |
| E21 | Cavity temperature probe (N6) fault. | Probe malfunction or disconnected wires. | Service. | Call service |
| E22, E26–E29 | Multipoint core probe (B10) fault, whole probe or points 1–4. | Probe malfunction or disconnected wires. | Service. | Call service |
| E23 / E24 / E25 | Steam generator (B4) / bypass (B5) / condenser (B3) probe fault. | Probe malfunction or miswired. | Service. | Call service |
| E34 | Steam generator drain pump fault during cleaning. | Calcium build-up or blockage in the drain pump, pump failure, or water-level probe failure. | Descale; service if it persists. | Call service |
| E36 | Steam temperature high. | Water supply shut off or low; calcium on the water injection pipe or flow restrictor; solenoid Y1 fault; blocked bypass hose. | Check the water supply and descale; service if it persists. | Call service |
| E40–E49 | A temperature probe is shorted to ground (B3, B4, B5, N6, N8, B10 and its points). | Probe miswired or failed. | Service. | Call service |
| E51 | No water in steam generator (roll-in models). | Water supply shut off, or relay board fault. | Open the water supply; service if it persists. | Call service |
| E53 / E54 | Fan motor over-temperature (upper / lower), above 320°F / 160°C. | Motor high-limit open or miswired, motor or fan wheel locked, fan wheel damaged. | Service. | Call service |
| E55 / E56 | Vent did not open within 60 seconds (lower / upper vent). | Vent valve monitoring switch or vent motor fault. | Service. | Call service |
| E57 | No rinse water detected for 60 seconds. | Water supply shut off or low pressure; flow switch dirty or failed. | Check the water supply; clean the flow switch. | Owner fix |
| E88 / E89 | Gas ignition failure (lower / upper). | Gas supply shut off or low; hot-surface igniter, flame sensor, ignition control or gas valve fault; plugged heat exchanger. | Check the gas supply. If it appears a third time after two resets, remove the oven from service and contact an authorized provider. | Call service |
| E90 / E91 | Gas combustion blower not at speed (lower / upper). | Power or speed-control cable not connected, blower blocked or failed, faulty control board. | Service. | Call service |
| E92 / E93 / E94 | Communication error between the control board and the interface board. | CAN cable connection or cable fault, relay or display board connector fault. | Turn the oven off, disconnect power, reconnect and turn on. Check the CAN cable connections; service if it persists. | Owner fix |
| E100 | A maintenance reminder has timed out. | A reminder expired without action. | Open the maintenance reminder screen, address the item and reset. | Owner fix |
| E101 / E102 | Ventless hood fault: no pressure / filters not present. | Filters missing, clogged or not seated; hood fan, filter switch or pressure switch fault. | Install, clean or re-seat the hood filters; a cook cycle cannot start until cleared. | Owner fix |
| E103 / E104 | Option board not communicating. | CAN cable between option board and control board, DIP switch setting, or incompatible software. | Service. | Call service |
| E105 | No or low water pressure. | Water supply not connected, shut off, or blocked (check the filter). | Connect or open the water supply; clean the inlet filter. | Owner fix |
| E108 | Cooling fan failure (board between 140°F and 176°F). | Cooling fan malfunction or blocked air intake. | Clear the intake; service if the fan has failed. | Call service |
| E109 | High-limit switch open. | An overheat condition, cooling fan failure, heat relay stuck closed, or a faulty high-limit connection. | Press the high-limit reset once. If the condition remains, contact an Alto-Shaam service provider. | Call service |
| E200 | SD card larger than 2 GB detected. | Wrong SD card size. | Contact service to order a replacement SD card. | Call service |
| E210–E217 | VFD under-voltage, over-voltage, overheating, motor over-current, current peak, EEPROM error, over-current, short circuit. | Blocked fan wheel, cooling fan failure, convection motor or VFD malfunction. | Service. | Call service |
Source: Alto-Shaam Combitherm CT PROformance operator\'s manual MN-35948 Rev 21, p. 79.
Before you call Alto-Shaam
- Refill and re-seat the water tank, and straighten any inlet or drain hose you can reach.
- Run the descale program if the oven has one, with the manufacturer's descaler, not vinegar.
- Switch the oven off at the wall for a minute and back on. One power-cycle is in nearly every manual; repeated resets are not.
- If the same code returns, note it with the serial number and book service. Every sensor, probe, fan or board code above is listed by Alto-Shaam as a service call.
Maintenance that prevents the water codes
Regular descaling with the product your manual names prevents most of the scale-related faults above. Affiliate links, at no cost to you.
Durgol Swiss Steamer descaler
A general-purpose steam-oven descaler, for ovens whose manual allows a generic one (Anova says any descaling liquid works). Miele and Thermador name their own descalers; use those instead.
View on Amazon · ~$21
Miele descaling tablets
The tablets Miele's own descale program expects. Clears the F20 message on DGC combi-steam ovens.
View on Amazon · ~$22
Weiman stainless microfiber cloth
A soft, non-abrasive cloth for drying the door and cavity after a steam cycle. Every manual we checked rules out scouring pads and abrasive cleaners.
View on Amazon · ~$9