Error D.69

Safety first

1) If you smell gas: get everyone out, do not operate electrical switches, do not use phones inside, shut off gas at the meter if you can do so safely, call your local gas emergency number immediately and a Gas Safe engineer. Do not try to relight the boiler.

2) If you suspect carbon monoxide (nausea, headache, Soot, yellow/irregular flame), get fresh air and call a professional and emergency services.

3) Do not open the boiler casing or attempt repairs on gas or electrical components. Only carry out non-intrusive checks and simple user-level actions.

Initial checks for homeowners (safe, simple checks)

1) Note the error: take a photo of the display showing D.69 and any other codes or status messages.

2) Reset the boiler once: consult the user manual for the correct reset procedure and press the reset button. Wait to see if the boiler attempts ignition and whether the code returns. Do not repeatedly reset more than twice; persistent lockouts indicate a fault needing an engineer.

3) Check gas supply: confirm other gas appliances (hob, gas fire) are working. If they are not, there may be a gas supply issue — contact your gas supplier.

4) Check house consumer unit and boiler isolation switch: ensure power is present and no fuses have tripped.

5) Check boiler water pressure: the gauge should normally be around 1.0–1.5 bar when cold. If pressure is low (well below 1.0 bar), you can repressurise using the filling loop according to the manual until the gauge reads around 1.2 bar, then close the filling loop and re-check. If you are unsure how to do this, stop and call a Gas Safe engineer.

6) Check external condensate pipe (if weather is cold): look for frost or ice blocking the condensate discharge pipe outside. If frozen, thaw the pipe by pouring warm (not boiling) water over it or use a warm pack, and insulate it afterwards. Do not use naked flames or hot tools.

7) Check for obvious blockages at the air intake and flue terminal: remove leaves, nests or debris outside that could obstruct airflow. Only clear external obstructions without opening the boiler.

8) Check the condensate trap and visible condensate pump (if you can access without opening live parts): make sure condensate pump float is not stuck and the trap is not overflowing. If you are unsure, wait for the engineer.

Specific diagnostic steps you can safely perform

1) After the initial reset and visual checks, try one more reset to see if the boiler lights. If the fault clears and does not return, monitor for recurrence — persistent or repeated D.69 means underlying fault remains.

2) If the boiler displays D.69 again immediately or after a short run, record the exact sequence (how many attempts, any other codes like flow/pressure faults) and do not keep resetting.

3) If water pressure was low and you repressurised, re-check for visible leaks around the boiler and system pipework. Persistent pressure loss suggests a leak or failing component and must be inspected by an engineer.

4) If other gas appliances work but the boiler does not and you have checked condensate and flue are clear, the likely causes are ignition electrode, ionisation sensor, gas valve, wiring or PCB faults — these require a Gas Safe engineer with test equipment.

When to call a professional

1) Call a Gas Safe-registered engineer if the D.69 code returns after a single reset, if you could not restore normal operation with the basic checks above, if you found low pressure that won’t hold, if the condensate or flue appears blocked but clearing does not help, or if you notice any gas smell or irregular flame behaviour.

2) Give the engineer the error code (D.69), any other fault codes, and the observations you made (pressure reading, whether other gas appliances work, whether condensate was frozen/blocked, whether reset cleared the fault temporarily). This speeds diagnosis.

What the engineer will likely check or do (for information)

1) Verify gas supply and pressure to the boiler and check isolation valves and strainer. 2) Check ignition transformer, electrodes and flame sensing/ionisation circuit. 3) Inspect the gas valve assembly, wiring harness and PCB for faults. 4) Check condensate discharge and condensate pump, air intake/flue routing and for recirculation or blockage. 5) Test water pressure sensors, pump operation and diverter valve if relevant.

Final notes

1) D.69 indicates failed ignition attempts and is a protection lockout — it is not usually fixed by prolonged resetting. 2) Simple homeowner fixes: reset once, check gas supply, check and if necessary repressurise the system, clear frozen/blocked condensate pipe and clear obvious external flue obstructions. 3) Any internal ignition, gas valve, electrode, wiring or PCB work must be done by a Gas Safe-qualified engineer. Keep the boiler off if you are unsure or if the fault persists, and arrange a professional inspection.