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Vaillant Fault Codes

Select a fault code to see its meaning, common causes and how to fix it.

• F.22 F.22 is a low water pressure (system protection) fault. Your Vaillant boiler has detected that there isn't enough water… Read more →
• F.28 F.28 is an ignition lockout fault. Your Vaillant boiler ran through its normal start-up sequence but failed to detect a… Read more →
• F.29 F.29 is a flame-failure lockout. It means your Vaillant boiler successfully lit but then lost the flame while running,… Read more →
• F.61 The F.61 code on a Vaillant boiler signals a gas valve control or communication fault. In plain terms, the boiler's… Read more →
• F.62 The F.62 code is a combustion safety fault. It appears when your Vaillant boiler detects that the flame has switched… Read more →
• F.75 No pressure change detected when the pump starts — typically a faulty pump or water pressure sensor. Read more →