BoilerFaultCodesVaillant D.68 Fault Code
Also written as D68 — same fault.
The Vaillant D.68 fault code means: your boiler is struggling to light its flame on the first try, though it may eventually start after several attempts.. It appears on 37 Vaillant models in our database.
Technical description: Unsuccessful ignitions in the first attempt
What causes the Vaillant D.68 fault?
This fault occurs when the boiler's internal computer detects that the gas has failed to ignite quickly enough during its initial startup phase. The most common reasons are a worn ignition lead failing to create a spark or a build-up of carbon on the sensing probe which prevents the boiler from 'seeing' the flame it has just lit.
This issue is more frequent in damp or cold winter months, as increased moisture or cold air can make it harder for a weak ignition system to successfully light the gas.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
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A cover plan would handle faults like D.68: no call-out fees, no surprise bills.
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Vaillant models that show the D.68 fault code
Click a model for the full fault code list and model-specific repair notes.
- Atmomax Repair: £100-280
- ecoFIT Pure 418 Repair: £100-280
- ecoFIT Pure 425 Repair: £100-280
- ecoFIT Pure 435 Repair: £100-280
- ecoFIT Pure 825 Repair: £120-250
- ecoFIT Pure 830 Repair: £120-250
- ecoFIT Pure 835 Repair: £100-280
- ecoMAX Repair: £150-300
- ecoMAX 613 Repair: £150-300
- ecoMAX 618 Repair: £120-250
- ecoMAX 622 Repair: £150-300
- ecoMAX 635 Repair: £150-300
- ecoMAX 824E Repair: £120-250
- ecoMAX 828E Repair: £150-350
- Ecomax Condensing 600/800 series Repair: £150-350
- ecoMAX System 612 Repair: £150-300
- ecoTEC Repair: £120-280
- ecoTEC 65kW Repair: £120-250
- ecoTEC Plus 615 Repair: £120-250
- ecoTEC Plus 620 Repair: £120-250
- ecoTEC Plus 625 Repair: £120-250
- ecoTEC Plus 630 Repair: £120-250
- ecoTEC Plus 635 Repair: £120-250
- ecoTEC Plus 840 Repair: £120-250
- ecoTEC plus aquaPLUS Repair: £120-250
- ecoTEC Pro / ecoTEC Plus Repair: £120-250
- ecoTEC sustain Repair: £120-250
- Home Combi Repair: £120-250
- Home System Repair: £100-280
- Thermocompact Repair: £120-250
- Turbomax 824/828 Repair: £120-250
- Turbomax Plus Repair: £120-250
- Turbomax Plus 824/828E Repair: £120-250
- Turbomax Plus 828 Repair: £120-250
- Turbomax Plus 828 E Repair: £150-300
- Turbomax Plus VUW 242E Repair: £150-350
- Turbomax Plus VUW 242EH Repair: £120-250
Source
Vaillant D.68 fault code information on this page is sourced and cross-checked against the official Vaillant service / installation manuals for each affected model.
- Vaillant ecoFIT Pure 835 manual (PDF)
- Vaillant ecoMAX manual (PDF)
- Vaillant ecoMAX System 612 manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026