Lelit Bianca: Troubleshooting The Water Sensor

The Lelit Bianca’s water-sensing system differs from most home espresso machines. It relies on three main components: the reservoir switch, the magnet sensor, and the magnet float.

Quick Note: The cable resembling a headphone jack provides power to the sensor assembly. Unplugging this cable completely disables the water-sensing system. If your machine is working normally, but is not detecting when the reservoir is empty, make sure that the power cable is securely plugged in at both ends.

When the sensor is plugged in, the system operates through a two-step verification process.

1. Reservoir Presence (The Switch)

• Reservoir Removed: The reservoir switch remains open. The CPU registers that the tank is missing, triggers the "no water" alarm, and disables operation.
  
  
• Reservoir Installed: A small plastic tab on the bottom of the tank depresses the reservoir switch. This signals to the CPU that the tank is correctly in place, allowing it to proceed to step two.
  

2. Water Level (The Magnet & Sensor)

Once the reservoir switch is engaged, the CPU uses a magnet sensor (located at the bottom of the machine's tank receptacle) to monitor the magnet float (located inside the water tank).

• Tank is Full: The float rises to the top of its housing, moving away from the bottom of the tank. Because the sensor cannot detect the magnet, the CPU confirms there is sufficient water, clears the alarm, and allows normal operation.
  
• Tank is Low/Empty: As the water level drops, the float sinks to the bottom of the tank. When the magnet gets close enough to the sensor to be detected, the CPU triggers the "no water" alarm to protect the machine.
  

Troubleshooting the Water Sensor

When the water-sensing system malfunctions, it generally fails in one of two ways:

1. False Alarm: The "no water" alarm stays on constantly, even though the reservoir is full and in place.
2. No Alarm: The machine fails to detect that the reservoir is empty or missing, risking damage to the pump.

Here is how to diagnose and fix both issues.

Issue 1: "No Water" Alarm is Stuck On (Reservoir is Full)

If the alarm won't clear, follow these steps in order:

• Check Reservoir Orientation: Ensure the water tank is installed correctly with the "Lelit" logo facing forward (toward you). If it is backward, the activation tab won't line up.
  
• Test the Physical Switch: 1. Remove the water reservoir. 2. Locate the small reservoir switch at the bottom of the machine's receptacle. 3. Press the switch using a pen tip or slim screwdriver. You should feel and hear a distinct click.
  
• Check the LCC Display: While holding the switch down as shown above, 
  look at the LCC screen:
  • If the alarm clears: The switch works, but the reservoir isn't hitting it. Check the bottom of the plastic tank to ensure the actuator tab isn't broken or bent. The switch may need a slight physical adjustment to make better contact.
  • If the alarm stays on (or there is no click): The switch itself is likely faulty or disconnected internally and needs to be replaced.
    

Issue 2: Machine Runs Empty (No Alarm Triggers)

If the machine keeps running when the tank is empty or completely removed, check the following:

• Check the Power Cable: Verify that the sensor's power cable (the one resembling a headphone jack) is firmly plugged in at both ends.
  
  
• Test the Reservoir Switch: Remove the tank entirely.
  • If the "no water" alarm pops up immediately, the switch is working. The issue lies with the magnet assembly (see below).
  • If the alarm does not pop up when the tank is removed, the switch is stuck in the "closed" position and needs replacement.
• Inspect the Float Magnet: If the machine only fails to detect a low water level (but knows when the tank is missing), the float magnet is the culprit:
  
  
  
  
  1. Look inside the reservoir's float housing.
  2. Ensure the float magnet is actually inside the housing.
  3. Orientation Matters: The dark end of the float contains the magnet. It must be installed facing downward.
  4. Ensure the housing cap is snapped securely in place so the float cannot escape.