370 Emergency

Viessmann 370 Fault Code

The Viessmann 370 fault code means: your boiler has detected a safety issue where the gas supply is failing to shut off correctly, causing the system to lock out for your protection.. It appears on 1 Viessmann model in our database.

Act immediately

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

Technical description: Gas or modulation valve will not close
Typical repair cost £280-550 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Viessmann models that show the 370 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Viessmann 370 fault code information on this page is sourced and cross-checked against the official Viessmann service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026