Schaerer Coffee Machine Message: Empty Waste Water Tank

What does Schaerer Empty waste water tank mean?

This message applies to Schaerer Coffee Soul machines fitted with an external waste water tank, which the manual calls an equipment variant. The table in chapter 14.4 says the external waste water tank is full and gives the cause as the fill level being reached. The listed actions are to remove the fill level sensor, empty and rinse the tank, and reinsert the sensor. The control watches the tank so that waste water cannot back up or overflow, and it holds drinks until the tank is emptied. The table does not say how much liquid the tank holds, how quickly it fills, or what the machine does with drink orders in the meantime. The rinse step keeps the tank from turning sour and keeps residue off the sensor, which matters because a coated sensor can keep reporting a full tank after emptying. The sensor has to go back correctly as well. If the machine drains to a fixed waste line instead of an external tank, this message does not apply.

Affected models and control systems

Schaerer Coffee Soul with the 10-inch or 12-inch display. The message is listed in the Soul operating instructions, chapter 14.4, and the manual gives no board revision or model limit for it.

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

• The display shows "Empty waste water tank (equipment variant)"
• Drinks stop until the tank is emptied
• The external tank is full of rinse water

Possible causes

Likely causes — what usually sits behind Empty waste water tank on this control. A technician confirms which one it is before any part is replaced.

• External waste water tank has reached its fill level
• Residue on the fill level sensor keeps it reading full after emptying
• The sensor was not put back correctly, so the machine sees a wrong level
• A kinked drain hose sends waste water to the tank slower or faster than expected

Safe checks before calling for service

How a technician diagnoses Empty waste water tank

1. Confirm the message and that the machine uses an external waste tank.
2. Check the drain hose for kinks and the connection for leaks.
3. Inspect the sensor for residue and seating.
4. Test the sensor signal with the tank empty and full.
5. Replace the sensor only if it does not follow the level.

Technical reference

Document

SOUL Operating Instructions (Schaerer, Original en)

Maker documentation

Schaerer owner support

Edition

Version 04-2026 (Doc. No. Shown as '-')

Models / control

Schaerer Coffee Soul (10-inch and 12-inch display)

Section

14 Troubleshooting - 14.4 Faults with display messages: 14.4.1 Fault tables pp. 223-226, 14.4.2 Error pp. 227-228, instruction messages p. 229 (PDF pages equal printed pages)

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.