A flooded print head occurs when filament accumulates inside the print head during a failed print job. This often results in a large mass of hardened material around the print cores and can cause permanent damage to components.

🔍 Issue Description

A flooded print head typically results from poor bed adhesion or hardware issues during printing. As the filament builds up around the print cores and hardens, it can become impossible to remove without damaging the hardware.

Though the UltiMaker S3 and S5 improved upon the UltiMaker 3 with better nozzle covers and alignment, flooded heads can still happen and these models do not detect this failure automatically. The UltiMaker S7 includes a fan bracket sensor to reduce severe damage, but this feature is not backward compatible.

⚠️ Common Causes & Prevention Tips

1. Bed Adhesion Failure

• Issue: If a print detaches, filament can flow back into the head or stick to the nozzle.
• Prevention: Clean the glass plate regularly and use appropriate adhesives. Check UltiMaker Marketplace for glue recommendations.

2. Nozzle Cover Problems

• Issue: A missing or worn nozzle cover can allow filament buildup or bracket damage.
• Prevention: Never print without the silicone cover. Inspect and replace it regularly—especially when using abrasive or high-temp materials.

3. Opening Fan Bracket

• Issue: The bracket can fall open due to impact or misalignment, allowing filament intrusion.
• Prevention: Ensure the bracket closes securely and is not bent. Some users use clips or bands to secure it, but this is not an official UltiMaker solution.

Tip: Monitor prints remotely using the UltiMaker Digital Factory camera when printing off-site.

🛠️ Solutions

Minor Flooding

With minor buildup, cleanup may be possible without replacing components:

1. Heat the affected print core to the material’s print temperature via the Configuration menu.
2. Open the fan bracket to access the heater block.
3. Use thermal gloves and tweezers to remove softened filament carefully.
4. Reduce temperature to 100–120°C to clean residual filament more easily.
5. Inspect all parts. Replace the nozzle cover if it is damaged.

Severe Flooding

In more extreme cases, multiple components may be damaged and require replacement:

• Do not use a heat gun inside the printer! Remove the head first.
• Try to heat and peel away material using a heat gun or the printer’s own heating if available.

Parts that commonly need replacement:

• Print Core(s): Replace if wires are damaged or heater block is deformed.
• Nozzle Cover: Replace if torn or melted.
• Front Fan Bracket: Replace if metal is bent and cannot be reshaped.
• Side Fan Bracket: Replace if cracked or deformed.

In the worst cases, the entire print head assembly may need to be replaced.

📞 Need Help?

Contact our support team  for further assistance if your printer has experienced a flooded head. We’re here to help!