Manufacturer guides
Vaillant error codes and fault guides
Browse 26 published, evidence-gated Vaillant guides. Each page states the supported model and region, official source, safe checks, and the point to stop.
26Published guides
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Verified catalog
Vaillant fault guides
25–26 of 26
VaillantUrgent
Heat pumpF.817
inverter-board mains-voltage fault
F.817 is identified by Vaillant support as inverter-board mains-voltage fault. Follow the official, model-scoped checks and service boundary below.
VaillantUrgent
Heat pumpF.9998
communication fault between the heat pump and eBUS controllers or wiring centres
F.9998 is identified by Vaillant support as communication fault between the heat pump and eBUS controllers or wiring centres. Follow the official, model-scoped checks and service boundary below.