Overview
E384 (False flame) means the boiler control is seeing a flame signal when the gas valve is supposed to be closed or when no burner flame should be present. Modern Potterton Assure boilers detect flame electrically (ionisation electrode) and report E384 when the control sees a continuous or spurious flame signal that doesn’t match the expected ignition sequence. Causes commonly include a faulty or contaminated flame sensing electrode, damaged wiring or poor connections in the flame detection circuit, a faulty PCB (control board) input stage, electrical interference or incorrect earthing, or rare electrical supply issues that alter signal behaviour. This is treated as a safety-related fault. The boiler will usually lock out or shut down to prevent unsafe operation. Because the underlying causes involve gas and safety-critical electronics, E384 is not something to attempt beyond basic user checks. A Gas Safe registered heating engineer should carry out any diagnostic measurements, repairs, or parts replacement. If the fault persists after simple user checks, turn the boiler off and call a qualified engineer promptly.
Possible Cause: False flame
Troubleshooting Steps
Safety precautions:
- If the boiler is locking out repeatedly or you smell gas, turn the boiler off, do not operate any electrical switches, ventilate the area, and leave the property. Call the gas emergency number immediately.
- Do not open the boiler casing or attempt internal electrical or gas work unless you are a qualified Gas Safe engineer. Working on gas appliances or PCB/electronics without certification is dangerous and illegal.
Initial homeowner checks you can safely do:
1. Record the error: note E384, how often it appears, and what the boiler was doing when it happened (lighting, running, standby).
2. Reset the boiler once using the manufacturer reset procedure (hold reset button 3–5 seconds) and see if the code returns. Do not repeatedly reset more than once or twice if the fault persists.
3. Check other gas appliances in the property (hob, oven) to confirm the gas supply is present. If no gas supply is present, contact your gas supplier.
4. Ensure the boiler’s external surroundings are dry, vents are clear and there is no obvious water ingress around the boiler casing that might affect electronics.
5. Check the boiler is receiving stable mains power at the fused spur and that no fuses/trips have occurred. If you are unsure about electrical checks, skip and call an engineer.
If the code persists, call a Gas Safe registered engineer. Typical professional diagnostic and repair steps the engineer will perform (do not try these yourself unless qualified):
1. Verify the fault code and examine the service log and live status of the boiler to reproduce the fault condition safely.
2. Visually inspect flame detection electrode and ignition assembly for damage, carbon build-up, incorrect positioning or contamination. Clean, re-seat, or replace the electrode if faulty.
3. Measure the flame signal (ionisation voltage/current) during ignition and during off periods to confirm whether a real or spurious signal is present. Confirm proper referencing to earth.
4. Check wiring and connectors between the electrode, gas valve and PCB for secure connections, corrosion, damaged insulation, or short circuits. Repair or replace wiring/terminals as required.
5. Test earthing and bonding of the boiler and surrounding pipework; poor earth can cause false flame signals.
6. Check for electrical noise or interference and measure mains voltage to rule out undervoltage or unstable supply (E385 can be related). Investigate other nearby electrical equipment if interference suspected.
7. Test the gas valve operation and related control outputs to ensure the boiler’s control sequences are correct and that the valve is not mechanically or electrically stuck.
8. If wiring, electrode and supply are correct but the fault remains, test or replace the PCB (control board) input stage responsible for flame sensing.
9. After repairs, the engineer will clear lockouts, run ignition and safety checks and confirm safe combustion and stable operation.
Final notes:
- E384 is a safety-related electrical/flame-detection fault. If a simple reset does not clear it, leave the boiler off and arrange a Gas Safe registered engineer. Do not attempt internal repairs yourself.
- Provide the engineer with the error code, the conditions when it happened, and any observations (smells, noises, frequency) to help diagnosis.
Helpful Resources
Boiler Manual
Download the official PDF manual for the Potterton Assure Combi and system.