BoilerFaultCodes
Heatline Boiler Fault Codes
350 fault codes across 15 Heatline boiler models — explained in plain English.
UK boiler brand owned by Vaillant Group. Entry-level to mid-range market.
Heatline fault codes on this site
We document 350 fault codes across 15 Heatline models, covering 186 distinct codes. Heatline boilers use letter-and-number codes such as F1, F2, F.22. Codes for 7 of these models are taken directly from the manufacturer's own service or installation manual.
Models covered: Capriz 28, Capriz Plus, Vizo 24, Vizo 28, Compact 30, Solaris, Monza, Capriz 25 System, Vizo Plus, Capriz 2, Capriz 25/28, C24, Compact 20, S24 / S30, Sargon.
Just want the most common Heatline problems?
The top 8 faults across the whole Heatline range — causes, DIY checks, repair costs.
High-severity Heatline fault codes
F1 F2 Low water pressure Overheat Lock-out
Your boiler is trying to start up but cannot light the gas flame needed to produce heat.
Capriz 28
Your boiler has lost the ability to accurately measure the water temperature, so it has safely shut down to prevent overheating.
Capriz 28
Your boiler has switched itself off because the water level inside the heating system has dropped too low to operate safely.
Capriz 28
Your boiler has detected that it is getting dangerously hot and has automatically shut itself down to prevent damage.
Capriz 28
Your boiler has stopped working as a safety precaution because it either failed to light or became too hot.
Capriz 28
All models
15 Heatline boiler models
Capriz 28
Combi Discontinued
Capriz Plus
Combi Discontinued
Vizo 24
Combi Discontinued
Vizo 28
Combi Discontinued
Compact 30
Combi Discontinued
Solaris
Combi Discontinued
Monza
Combi Discontinued
Capriz 25 System
System Discontinued
Vizo Plus
Combi Discontinued
Capriz 2
Combi
Capriz 25/28
Combi Discontinued
C24
Combi Discontinued
Compact 20
System Discontinued
S24 / S30
Combi Discontinued
Sargon
Combi Discontinued
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