Alto-Shaam Combi Oven Error Code E105: No or Low Water Pressure
E105 No or Low Water Pressure means the water pressure switch is not activated. Check that the water supply is connected, open and unobstructed, and look at the water filter.
Medium: water functions stop until pressure is restored.
- Code
- E105
- Maker
- Alto-Shaam
- Equipment
- Combi ovens
- Applies to
- Combitherm CT PROformance (CTP) and CT Classic (CTC)
What does Alto-Shaam error code E105 mean?
A pressure switch on the oven's water inlet closes when enough water pressure is present. The control looks at that switch before it runs any function that needs water. If the switch is not activated, the control posts E105 No or Low Water Pressure. The manual lists three causes, all on the supply side: the water supply is not connected, it is shut off, or the supply is blocked or obstructed, with the filter named as the first place to look. That makes E105 one of the few codes an operator can often clear alone, because the usual cause is outside the oven. It is a check on the supply, not on the steam generator, so it differs from E01 or E51, where water was called for but did not reach a probe. Pressure also drops when other equipment draws water at the same time. The CT Express manual lists E105 as Low Water Pressure too.
Affected models and control systems
CT PROformance and CT Classic ovens, 6-10 to 20-20, electric and gas. The CT Express list shows E105 as Low Water Pressure.
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
- E105 No or Low Water Pressure on the display
- Steam, rinse or cleaning functions not starting
- Weak flow from the inlet hose
Possible causes
Listed in Alto-Shaam's documentation
- Water supply not connected
- Water supply shut off
- Supply blocked or obstructed, including the filter
Other likely causes — what usually sits behind error code E105 on this control. A technician confirms which one it is before any part is replaced.
- A water filter cartridge clogged after months in use
- Building pressure falling when a dishwasher or ice machine fills at the same moment
Safe checks before calling for service
- Check that the water supply hose is connected to the oven and the shutoff valve is fully open.
- Look at the water filter and replace the cartridge if it is due.
- Make sure the hose is not kinked or crushed behind the oven.
- If E105 returns, note the time of day and whether other water equipment was running.
How a technician diagnoses error code E105
- Read the code and confirm the supply at the oven inlet.
- Measure static and flowing pressure.
- Inspect the inlet strainer and the line filter.
- Test the pressure switch for continuity when pressure is present.
- Replace the switch only if it stays open with good pressure.
- Pressure switch testing is done with the water line live and the switch wired into the control circuit.
- Inlet parts sit behind panels near line voltage.
- A switch that sticks open cannot be told from a pressure problem without a gauge.
How error code E105 differs from similar codes
E01 and E51 report that the generator did not fill; E57 reports no rinse water flow; E105 reports the inlet pressure switch not activated.
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 E105 usually the water supply?
Yes. All three causes the manual lists are on the supply side.
Can I keep cooking dry?
The oven tries to resume, but functions needing water will not run.
Does the filter matter?
A clogged filter is the first obstruction the manual names.
Need help with Alto-Shaam error code E105?
A technician confirms the cause on site and gives you the price in writing before any work starts.