E78 — Minimum gas valve current out of range

What does E78 mean?

The boiler has detected that the minimum current supplied to the gas valve is outside its normal operating limits.

• Low gas supply pressure.
• Incorrect positioning or integrity of the sensing electrode.
• Flue gas recirculation.
• Incorrect CO2 value during ignition.

Click steps to track your progress.

1. 1

   Ensure the main gas supply to the property is open and other gas appliances are working.

2. 2

   Turn off the main power supply to the boiler, wait 30 seconds, then turn it back on.

3. 3

   If the error persists, a qualified technician should check the gas supply pressure, sensing electrode, and enable automatic calibration.