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Error code · Alto-Shaam · Combi ovens

Alto-Shaam CT Express Combi Error Code E103: Ventless Hood Pressure

E103 Ventless Hood Fault -- Pressure Failure means the ventless hood is not operating properly. Check the hood power switch, the fan rotation, the filters, and the pressure switch and its tube.

Medium · inspection needed

Medium: the hood cannot prove airflow and the oven may stop.

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Code
E103
Maker
Alto-Shaam
Equipment
Combi ovens
Applies to
CT Express 4-10ESi, 4-10ESiVH, 4-10CCi, CTX4-10E, CTX4-10EC, CTX4-10EVH

What does Alto-Shaam error code E103 mean?

The ventless hood pulls oven exhaust through filters with a fan, and a pressure switch proves that air is actually moving. If the hood is not operating properly, the control posts E103 Ventless Hood Fault -- Pressure Failure. The CT Express manual lists five causes: the hood power switch is off or defective, the hood fan is not operating or is turning the wrong way, the filters are clogged, the pressure switch tube is plugged or disconnected, or the pressure switch or its connection is defective. Its actions are to check the hood power switch, the fan rotation, the filters, and the pressure switch and its tube. A fan turning the wrong way moves air in the wrong direction, so the pressure switch never closes, which usually appears after a wiring change. This number is specific to the CT Express controller, and the CT PROformance and CT Classic use E103 for a different message about an option board.

Affected models and control systems

The ventless-hood option on the CT Express range, models 4-10ESi, 4-10ESiVH, 4-10CCi, CTX4-10E, CTX4-10EC and CTX4-10EVH.

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

  • E103 Ventless Hood message on the display
  • Little airflow at the hood
  • Hood fan silent or running the wrong way

Possible causes

Listed in Alto-Shaam's documentation

  • Hood power switch off or defective
  • Hood fan not operating or turning the wrong way
  • Filters clogged
  • Pressure switch tube plugged or disconnected
  • Pressure switch or connection defective

Other likely causes — what usually sits behind error code E103 on this control. A technician confirms which one it is before any part is replaced.

  • A small hose to the pressure switch kinked or pinched when the hood was last serviced
  • Grease soaking through the filter and blocking the sensing tube

Safe checks before calling for service

✓ What an operator can do
  1. Check that the hood power switch is on.
  2. Listen for the hood fan when a program starts.
  3. Check that the filters are clean and not clogged.
  4. If E103 returns, note whether the fan runs and tell the technician when the filters were last changed.

How a technician diagnoses error code E103

  1. Read the code and confirm the hood option.
  2. Check the hood power switch and fan rotation direction.
  3. Inspect the filters and the pressure switch tube for blockage or disconnection.
  4. Test the pressure switch and its wiring.
  5. Replace the fan, switch or tube that fails.
! Leave this to a technician
  • The hood fan and switch use live voltage.
  • Fan rotation is checked with the hood powered.
  • Grease in the hood is a fire risk.

How error code E103 differs from similar codes

E102 reports the filters not present; E103 reports the hood pressure failure on the CT Express.

Technical reference

Document
Combitherm CT Express Technical Manual (4-10ESi, 4-10ESiVH, 4-10CCi, CTX4-10E, CTX4-10EC, CTX4-10EVH)
Maker documentation
Alto-Shaam owner support
Edition
MN-36008 (Rev. 9) 03/16
Models / control
CT Express 4-10ESi, 4-10ESiVH, 4-10CCi, CTX4-10E, CTX4-10EC, CTX4-10EVH
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.

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E103Questions about Alto-Shaam error code E103
Can a wrong fan direction cause E103?

Yes, it is listed with the fan not operating.

Is E103 the same on a CT Classic?

No, there it refers to an option board.

Do clogged filters matter?

Yes, they reduce airflow so the pressure switch does not close.

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