Error 20; unit indicates condensate drainage problem or condensate level fault.

Safety: Turn off power. Condensate is mildly acidic; wear gloves and eye protection.

• Locate condensate trap: At the base of the combustion chamber, remove the trap according to the manual.
• Clean trap: Rinse out sludge and debris with clean water. Ensure the internal baffles are clear.
• Check drain hose: Follow the hose to the drain point. Clear any kinks or blockages. Ensure the pipe slopes continuously downward and is protected from freezing.
• Reassemble and test: Refit the trap (pre‑fill with water if required), restore power, and run the heater. Check for leaks and proper drainage.

Note: If the condensate repeatedly blocks, the installation may not meet Immergas guidelines and should be reviewed by an installer.