Viessmann Pre-Ignition Sequence Stalled

Boiler fan runs but burner does not ignite, no error code displayed

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Weak ignition spark, marginal gas pressure, partially blocked burner, failing gas valve coil

Safety: Ignition issues involve gas; only qualified personnel should adjust gas components.

Observe sequence: Listen for fan, then ignition clicks. If clicks are weak or absent, the ignition electrode or cable may be faulty.
Check condensate and flue: Ensure condensate trap and flue are clear to allow proper combustion air flow.
Technician diagnostics: A professional should check ignition voltage, electrode condition, burner cleanliness, and gas valve operation, and then perform combustion analysis.

Professional Required 5/5

Ignition Electrode

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