Error D.68

Safety precautions:

1. If you smell gas, hear hissing, or suspect a strong gas leak: do not operate the boiler, do not switch electrical items on or off, ventilate the property, evacuate all occupants and call your gas emergency number immediately.

2. If anyone has symptoms of carbon monoxide exposure (headache, nausea, dizziness), get fresh air, seek medical help and call an emergency service. Shut down the boiler only if it is safe to do so and you are not exposed to fumes.

3. Do not open the boiler casing or touch internal components. High voltage and gas parts inside the boiler are dangerous. Only perform external, non-invasive checks.

Initial homeowner checks you can safely do:

1. Read and note the full fault code and any other displayed codes or history (D.68 and how many attempts). This information is useful for the engineer.

2. Try a standard reset: follow the boiler instructions (usually press and hold reset for up to 10 seconds). If the boiler starts and runs normally for a while, monitor it — if D.68 returns, further investigation is needed.

3. Check for power and gas supply: ensure the boiler is powered (fuse, isolator switch) and that other gas appliances (hob, oven) are working. If no gas to the house, contact your gas supplier.

4. Check the external flue and air intake for obvious blockages (leaves, bird’s nest, snow or ice). Remove light obstructions safely from outside if accessible without climbing or risking injury.

5. Check the condensate discharge: in freezing weather the condensate pipe can freeze. If safe to reach, thaw a frozen condensate pipe with warm (not boiling) water or wrap it with a warm cloth. Do not force or chip ice.

6. Check system water pressure on the boiler gauge; while low pressure is not a primary cause of ignition failure, some faults interact. If pressure is very low, the boiler may lock out for safety — consult instructions before repressurising and do not improvise gas or internal electrical work.

7. Confirm the gas isolator valve near the boiler is in the open position (do not attempt to adjust internal gas components).

If the simple checks don’t clear the fault or the fault returns:

1. Do not keep resetting the boiler repeatedly — repeated failed ignition attempts can mask the real fault and leave the unit in lockout.

2. Prepare information for the engineer: make, model, age of boiler, exact fault code (D.68), when the problem started, whether reset temporarily fixed it, whether other gas appliances are affected, recent freezing weather, or recent servicing/works to the gas or heating system.

What a Gas Safe engineer will typically check and do (for information):

1. Verify gas supply and test inlet/gas pressure to the appliance; check the gas meter and the property regulator. Look for air in the gas line.

2. Inspect the flue, air intake and condensate route for blockages or recirculation issues.

3. Test ignition components: ignition transformer, ignition lead, electrode condition and correct electrode gap; check for oil/condensate contamination or electrode contact with the burner.

4. Measure flame detection/ionisation signal and check earthing/grounding to ensure the flame is being sensed correctly.

5. Check gas valve operation and coil resistance (service spec values), check for correct gas valve calibration and that the correct gas family/restrictor is fitted.

6. Inspect wiring harness and connectors for continuity, corrosion or intermittent connections; check PCB operation and timings.

7. Test for condensate in the combustion chamber or blocked condensate drain that could impair ignition.

8. Replace any failed ignition parts, correct wiring/earth faults, or replace the gas valve/PCB as needed and safe.

Final notes and when to call a professional:

1. If the simple external checks (reset, clear condensate, clear flue/air intake, confirm gas supply) do not resolve D.68, stop and call a Gas Safe–registered heating engineer. Ignition faults involve gas, high voltage and safety controls and must be diagnosed and repaired by a qualified engineer.

2. When calling, give the engineer the fault code D.68, any other codes, what checks you have already done, and whether other gas appliances are affected. This speeds diagnosis and helps the engineer bring correct parts.

3. Do not attempt to swap internal components, work on the gas valve, or adjust ignition electrodes yourself. Those actions are hazardous and may make the appliance unsafe and invalidate warranties/insurance.