BoilerFaultCodesWhat the manual says
Manufacturer manualAverage ignition times
From this model's manual
Verified against the Vaillant/Vaillant Ecotec Plus Pro 839592 05 2006 installation & service manual.
What causes this fault?
This issue occurs when the boiler's control board detects that the burner is taking a few seconds longer than normal to establish a stable flame. The most common reasons are worn-out spark electrodes that can no longer create a strong spark or a build-up of carbon deposits on the sensing probe which prevents it from 'seeing' the flame quickly.
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 →
Boiler cover options
Avoid the next call-out bill
A cover plan would handle faults like D.64: no call-out fees, no surprise bills.
Approved partner
Get a quote →
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Affiliate links. We may earn a commission at no extra cost to you.
Related fault codes
All 135 fault codes on the ecoTEC plus 612 R1 VU GB 126/3-5
Seeing a different code? Every code this model can display, in one place.
3596conConnectionD,11D.0D.1D.2D.3D.4D.5D.7D.8D.9D.10D.12D.13D.17D.18D.20D.22D.23D.25D.27D.28D.30D.33D.34D.35D.40D.41D.44D.47D.50D.51D.60D.61D.65D.67D.68D.69D.70D.71D.72D.75D.76D.77D.78D.80D.81D.82D.83D.84D.90D.91D.93D.96D.97F.0F.1F.10F.11F.13F.20F.22F.23F.24F.25F.27F.28F.29F.32F.49F.61F.62F.63F.64F.65F.67F.70F.71F.72F.73F.74F.75F.76F.77F.78F70P.0P.1P.2P.3P.4P.5P.6S. 2S. 5S.0S.1S.3S.4S.6S.7S.8S.10S.11S.13S.14S.15S.16S.17S.20S.21S.22S.23S.24S.25S.26S.27S.28S.30S.31S.32S.34S.36S.41S.42S.52S.53S.54S.96S.97S.98