Vaillant Boiler Error Codes

A plain-English reference to 17 common Vaillant fault codes — what each means, what causes it, and when to call a licensed BC gas technician.

Vaillant ecoTEC boilers show an "F" fault code on the display when a safety circuit trips. One of the oldest heating names in the world (since 1874), Vaillant is refined and reliable — and its F-codes pinpoint the fault precisely. This reference explains the common Vaillant fault codes, what each means, and why ignition, flame, gas-valve and overheat faults need a licensed BC gas technician rather than repeated resets. Note that some Vaillant parts carry lead times in BC, so accurate diagnosis matters.

Smell gas? Leave the building immediately and call 911 or FortisBC at 1-800-663-9911 from outside. Never bypass a safety lockout or attempt gas work yourself — in BC it must be done by a licensed gas fitter.

Temperature-sensor fault

Vaillant F.0Flow NTC Sensor Interrupted Vaillant F.1Return NTC Sensor Interrupted

Over-temperature / high-limit

Vaillant F.20Safety Shutdown — Overheat

System water-pressure fault

Vaillant F.22Low Water Pressure / Dry Fire Vaillant F.73Water Pressure Sensor Signal Low Vaillant F.75Pump / Pressure-Rise Fault

Water-flow / circulation fault

Vaillant F.23Temperature Spread Too Large Vaillant F.24Temperature Rise Too Fast

Flame failure

Vaillant F.27Flame Simulation Fault Vaillant F.29Flame Loss During Operation

Ignition fault

Vaillant F.28Ignition Failure on Start-Up

Combustion-fan fault

Vaillant F.32Fan Fault

Communication fault

Vaillant F.49eBUS Fault

Gas-supply / gas-valve fault

Vaillant F.61Gas Valve Control Fault Vaillant F.62Gas Valve Shutoff Delay Fault

Control-board (PCB) fault

Vaillant F.63EEPROM / PCB Fault

Condensate fault

Vaillant F.77Condensate Pump / Flue Damper Fault

Vaillant error codes — FAQ

Why is my Vaillant boiler showing an error code?

Vaillant boilers display a fault code when a safety circuit detects a problem — for example with ignition, flame, water flow, temperature or venting. The code points to the affected system. The boiler shuts down to protect itself; a licensed technician then diagnoses the true root cause before repair.

Can I just reset my Vaillant boiler?

A single reset after a one-off event is usually fine, but repeated resets without fixing the cause can be unsafe — especially for ignition, gas and venting faults — and can cause further damage. If the code returns, switch the boiler off and call GasBoilers.ca at 604-359-1081.

Do you repair all Vaillant boiler models in Greater Vancouver?

Yes. Our Red Seal–certified, gas-licensed technicians service Vaillant ecoTEC plus and ecoTEC exclusive condensing boilers & combis across Vancouver, Burnaby, Surrey, Richmond, the Tri-Cities and the rest of Greater Vancouver. Same-day appointments are often available.

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Error codes by brand

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