Alto-Shaam Combi Oven Error Code E101: Ventless Hood No Pressure
E101 Ventless Hood Fault - No Pressure means the power switch or pressure switch of the ventless hood is not closed. Check that the filters are installed and not clogged, and call for service if it returns.
Medium: the hood cannot prove airflow and the oven may stop until it does.
- Code
- E101
- Maker
- Alto-Shaam
- Equipment
- Combi ovens
- Applies to
- Combitherm CT PROformance (CTP) and CT Classic (CTC)
What does Alto-Shaam error code E101 mean?
A ventless hood cleans the oven's exhaust with filters and a fan instead of a duct to the outside. The control relies on switches to confirm the hood is working: a filter switch, a pressure switch that proves air is moving, and the hood's power switch. If the power switch or pressure switch is not closed, the control posts E101 Ventless Hood Fault - No Pressure. The manual lists four things to check: filters that are missing or clogged, the hood fan, the filter switch, and the pressure switch. Clogged filters are the usual cause in a busy kitchen, because grease builds up and the fan can no longer pull air through. If the filters are clean and in place and the code stays, the fan or a switch is the next step. E101 concerns airflow pressure, while E102 is about the filter switches not closing.
Affected models and control systems
CTP and CTC combis that have a ventless hood fitted, in sizes 6-10 up to 20-20. An oven vented through a duct does not show this message.
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
- E101 Ventless Hood Fault - No Pressure on the display
- Weak or no airflow from the hood
- Steam or cooking smoke escaping into the room
Possible causes
Listed in Alto-Shaam's documentation
- Filters missing or clogged
- Hood fan problem
- Filter switch problem
- Pressure switch problem
Other likely causes — what usually sits behind error code E101 on this control. A technician confirms which one it is before any part is replaced.
- Grease-loaded filters that look intact but block the airflow
- A filter seated slightly crooked so its switch never closes
Safe checks before calling for service
- Check that the hood filters are fitted correctly and seated.
- Remove and clean or replace the filters as the manual directs, after the oven has cooled.
- Listen for the hood fan when a program runs.
- If E101 returns, tell the technician when the filters were last cleaned and what the oven cooks.
How a technician diagnoses error code E101
- Read the code and ask about filter changes.
- Check filter placement and the filter switch.
- Verify the hood fan runs and measure its supply and current.
- Test the pressure switch with a manometer or by continuity as the airflow is made.
- Replace the fan or switch after the test shows which one failed.
- The hood fan and switches are wired with live voltage.
- Measuring the pressure switch needs the hood running and opened.
- Grease buildup in a hood is a fire concern.
How error code E101 differs from similar codes
E102 reports filter switches not closed; E101 reports the power or pressure switch not closed.
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.
Related Alto-Shaam combi oven error codes
Is the hood part of the oven?
The ventless hood is a separate option, but the oven monitors it.
Will new filters fix it?
If clogging is the cause, yes.
Why is it called No Pressure?
Because the pressure switch is the one proving airflow.
Need help with Alto-Shaam error code E101?
A technician confirms the cause on site and gives you the price in writing before any work starts.