F.02
Viessmann F.02, Safety chain lockout
HIGHMultiple possible causes across the safety chain, overheat, flame supervision, low water. Manufacturer diagnostic required.
Same-day repairs on every Viessmann model, Vitodens 050-W, 100-W, 111-W and 200-W, by Gas Safe engineers experienced on Viessmann's stainless steel Inox-Radial heat exchangers. Manufacturer-approved parts, honest quotes, one-visit fixes wherever possible.
Average reply under 10 minutes. No obligation.
Call 020 3000 0000Viessmann is a premium German brand and, in truth, the boilers we're called to less often than any other. The Inox-Radial stainless heat exchanger is genuinely excellent and outlasts most competitors. When faults do appear on Vitodens units across London, they cluster around F.22 low-pressure lockouts (typically a slow system leak, not the boiler itself), F.38 flame supervision faults, and F.02 safety chain lockouts on older 100-Ws that haven't been serviced on schedule.
Viessmann parts require a slightly more specialist supplier network than Vaillant or Worcester, but our engineers know it well and can source most components same-day across London. Where a Vitodens is out of warranty and facing a major fault, we'll always give you the honest repair-vs-replace numbers, these boilers are worth keeping.
Multiple possible causes across the safety chain, overheat, flame supervision, low water. Manufacturer diagnostic required.
Sensor replacement, a single-visit fix once diagnosed.
Sludge or a failed thermistor. Don't keep resetting, book a proper diagnosis.
Repressurise to 1.5 bar. Recurring F.22 means a leak, book a trace.
Ionisation electrode, gas valve or PCB. Engineer only.
Showing a different code? Call 020 3000 0000 and read it to us, we'll tell you what it means over the phone, free.
If your Viessmann is over 12 years old and facing a major repair, we'll give you honest repair-vs-replace numbers on site, see our new boiler installation options.
Fixed quote before work begins, 12-month workmanship guarantee, genuine or manufacturer-approved parts.
"F.22 recurring after a bathroom refit. Traced a small leak on a new towel-rail joint, fixed properly."
"F.38 flame supervision fault. New ionisation electrode and full combustion check, running clean."
"F.05 flue sensor. Sourced the manufacturer part same day, fixed on the second visit within 24 hours."
Viessmann-trained Gas Safe engineers across all 32 London boroughs, 24/7.