Boiler displays E06; internal electronics appear dead or unstable, or boiler resets intermittently.

Safety first: Turn off power at the isolator and verify with a tester that no voltage is present before touching internal wiring.

• Check mains supply: Confirm that the correct voltage is present at the boiler terminals (typically 230 V AC). Inspect the external isolator and breaker for signs of overheating or loose connections.
• Inspect internal connections: Remove the front cover and check the tightness of the mains terminal block and earth connection. Look for burnt or discoloured wiring.
• Examine the PCB: Look for obvious damage such as burnt tracks, bulging capacitors, or scorch marks on the main control board.
• Reset and monitor: After tightening connections, restore power and observe the boiler. If E06 recurs or the display flickers, the PCB power supply is likely defective.
• Replace PCB: PCB replacement should be carried out by a qualified engineer, ensuring the correct Elnur part number and any configuration/jumper settings are transferred from the old board.

Warning: Never attempt to repair a PCB at component level unless you are an electronics professional; incorrect repair can defeat safety circuits.