Emergency
F.352 on Viessmann Vitodens 200-W B2KE-19

The boiler has shut itself down because it has detected more carbon monoxide than it should, which usually means its exhaust pipe is blocked, leaking, or not venting properly, so please switch it off and get a Gas Safe engineer to check it.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

What the manual says

Manufacturer manual

Burner in a fault state. CO limit within appliance exceeded. Check entire flue gas path for flue gas recirculation, leaks, flue gas back pressure caused by water pocket (if flue system fall is insufficient), constrictions and blockages. Repair flue system if necessary. Reset device.

From this model's manual
Verified against the Viessmann/Viessmann Vitodens 100 W Wb1a installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

This is a emergency severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

F.351View →F.353View →

All 170 fault codes on the Vitodens 200-W B2KE-19

Seeing a different code? Every code this model can display, in one place.

F.7F.8F.9F.10F.11F.12F.13F.14F.15F.16F.29F.30F.49F.50F.57F.58F.59F.62F.63F.65F.67F.68F.69F.70F.71F.72F.73F.74F.77F.89F.91F.92F.93F.94F.100F.104F.142F.160F.161F.162F.163F.182F.183F.184F.185F.299F.342F.345F.346F.348F.349F.350F.351F.353F.354F.355F.357F.359F.361F.365F.366F.367F.368F.369F.370F.372F.373F.375F.377F.378F.380F.381F.382F.383F.384F.385F.386F.387F.388F.395F.396F.399F.400F.401F.402F.403F.404F.405F.406F.408F.410F.416F.417F.418F.425F.426F.427F.428F.429F.430F.432F.433F.436F.437F.440F.441F.442F.443F.444F.445F.446F.447F.448F.449F.450F.451F.452F.453F.454F.455F.456F.457F.458F.461F.462F.463F.464F.467F.468F.471F.473F.474F.517F.527F.528F.530F.538F.539F.540F.542F.543F.544F.545F.546F.547F.574F.575F.576F.577F.578F.579F.580F.581F.582F.666F.667F.668F.669F.670F.671F.672F.673F.682F.683F.684I.55I.56I.57I.59

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