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Smell gas? Leave the property, avoid switches and flames, and call the National Gas Emergency line free on 0800 111 999 first. Once you're safe, call us on 020 3000 0000 for the repair.
  • VIESSMANN SPECIALISTS · LONDON-WIDE

Viessmann Boiler Repair in London

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.

Common Viessmann codes we clear daily

F.02

F.05

F.20

F.22

F.38

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The faults we see most on Viessmann boilers in London

Viessmann 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.

Viessmann error codes explained

F.02

Viessmann F.02 — Safety chain lockout

HIGH

Multiple possible causes across the safety chain — overheat, flame supervision, low water. Manufacturer diagnostic required.
F.05

Viessmann F.05 — Flue gas temperature sensor fault

MEDIUM

Sensor replacement — a single-visit fix once diagnosed.

F.20

Viessmann F.20 — Overheat lockout

HIGH

Sludge or a failed thermistor. Don’t keep resetting — book a proper diagnosis.
F.22

Viessmann F.22 — Low water pressure or dry firing protection

MEDIUM

Repressurise to 1.5 bar. Recurring F.22 means a leak — book a trace.
F.38

Viessmann F.38 — Flame supervision — no flame signal

HIGH

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.

Every Viessmann model, covered

Vitodens 050-W
Vitodens 100-W
Vitodens 111-W

Vitodens 200-W

Vitodens 222-F

Vitocrossal

Vitoladens

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.

Viessmann repair costs in London

Diagnostic visit

£0–£95 (free with any repair)

F.22 repressurise + leak trace

£120–£240

Flue temperature sensor (F.05)

£160–£280

Ionisation electrode (F.38)

£160–£300

Expansion vessel recharge/replace

£140–£380

PCB replacement

£360–£620

Fixed quote before work begins, 12-month workmanship guarantee, genuine or manufacturer-approved parts.

Recent Glow-worm jobs across London

JOB / SW3 / VITODENS 100-W

“F.22 recurring after a bathroom refit. Traced a small leak on a new towel-rail joint, fixed properly.”
— CHELSEA

JOB / NW3 / VITODENS 200-W

“F.38 flame supervision fault. New ionisation electrode and full combustion check, running clean.”
— HAMPSTEAD

JOB / W8 / VITODENS 111-W

“F.05 flue sensor. Sourced the manufacturer part same day, fixed on the second visit within 24 hours.”
— KENSINGTON

Viessmann repair FAQs

Are Viessmann boilers worth the money?
Yes — the Inox-Radial stainless heat exchanger and overall build quality genuinely justify the premium. Well-serviced Vitodens units regularly reach 15+ years.
For the common faults — pressure, flame supervision, sensors — usually yes. For rarer PCB or hydraulic-block work we may need a next-day return once the manufacturer part is sourced.
Yes — genuine or manufacturer-approved parts every time, which protects the warranty on newer units.
Depends on model and install date. If it is, we’ll tell you before doing any chargeable work so you can decide whether to go through the manufacturer route.
With annual servicing, 15 years is realistic and 20 is possible on the 200-W range. The stainless heat exchanger is the key advantage.

Viessmann down? We're already nearby.

Viessmann-trained Gas Safe engineers across all 32 London boroughs — 24/7.

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