my ice maker just blinks the 'add water' light even though the tank is completely full.

Diagnosis

The "Add Water" indicator on the Aglucky HZB-12B is triggered by a magnetic float switch located in the internal reservoir. This float is a small, white plastic cylinder that slides vertically on a guide post. When the water level is sufficient, the float rises, triggering a reed switch that tells the control board the unit is ready to operate. When the light blinks despite a full tank, it means the float is physically stuck in the "down" position or the magnetic connection has been compromised. This failure is typically caused by calcium carbonate buildup (limescale) from hard water. Mineral deposits create a gritty friction layer on the guide post, effectively "gluing" the float in place. In some cases, a small piece of debris or a slime biofilm can lodge underneath the float, preventing it from rising. You can confirm this by looking into the reservoir; if the water is full but the white float is sitting at the bottom of its track, the sensor is failing to register the volume.

How to Fix It

To resolve a stuck float and reset the sensor, follow these precise steps:

1. Unplug the unit from the wall outlet to prevent electrical shorts while working with water.
2. Remove the removable water tank if your specific sub-model has one, or clear the interior of any remaining ice cubes to gain a clear line of sight to the bottom of the reservoir.
3. Locate the white plastic float cylinder. It is usually positioned near the water inlet/outlet area of the internal sump.
4. Using a clean cotton swab or a thin plastic probe, gently push the float down and let it snap back up. Repeat this motion 10 to 15 times. You should feel a slight "click" or a smooth glide; if it feels gritty, it is clogged with minerals.
5. If the float is stubborn, pour 1 cup of warm (not boiling) distilled white vinegar directly onto the float and the guide post. Let it sit for 15 minutes to dissolve the calcium deposits.
6. Use a soft-bristled toothbrush to gently scrub the guide post and the sides of the float.
7. Wipe the area clean with a damp cloth, refill the reservoir to the "Max" line, and plug the unit back in.

If That Didn't Work

• Perform a full system descale. Mix a solution of one part white vinegar to three parts warm water. Fill the reservoir and run a full ice-making cycle. Discard the first three batches of ice. This removes internal scale from the pump and sensors that manual scrubbing cannot reach.
• Check for airlocks in the pump. If the unit was tilted during transport or cleaning, an air bubble can trap the water away from the sensor. Tilt the machine gently forward and backward while it is powered on to burp the air out of the internal plumbing.
• Inspect the magnetic reed switch. If the float moves freely but the light still blinks, the magnetic coupling may have failed. Use a small handheld magnet and move it slowly around the exterior of the plastic housing where the float resides; if the "Add Water" light turns off, the float's internal magnet has lost its potency and the sensor assembly needs replacement.
• Hard reset the control board. Unplug the unit for exactly 30 minutes. This clears the volatile memory of the HZB-12B logic board and forces a fresh sensor poll upon startup.

Heads Up

• Never use boiling water to descale the unit; this can warp the plastic reservoir and damage the silicone seals, leading to internal leaks.
• Always use filtered or distilled water to prevent the "Add Water" error from recurring. Tap water with high mineral content will cause the float to stick again within 30 to 60 days.
• Do not use harsh chemical detergents or bleach to clean the reservoir, as these can degrade the magnetic properties of the float sensor.
• Ensure the unit is placed on a perfectly level surface. If the machine is tilted, the float may lean against the guide post, creating friction that triggers a false "low water" reading.