Saunier Duval Boiler Fault Codes

216 fault codes across 22 Saunier Duval boiler models — explained in plain English.

French brand owned by Vaillant Group. Popular across Europe.

216 fault codes
22 models documented
6 currently sold
16 legacy models

Saunier Duval fault codes on this site

We document 216 fault codes across 22 Saunier Duval models, covering 87 distinct codes. Saunier Duval boilers use a mix of numbered codes and light or status indications. Codes for 18 of these models are taken directly from the manufacturer's own service or installation manual.

Models covered: Themaclassic F24E, Themaclassic Plus F30E, Thelia 23E, Isofast F28E, Isomax F30E, Ecosy 24E, Opalia F24E, Isotwin F30E, SD 30e, Isofast, Sylva, Xeon 120 FF, Enviroplus, Semia Condens F30 E, Thema F 30 E Plus, Xeon 30ff, Themaclassic F35E, Xeon 18 HE, Xeon Condens 30, Xeon 40ff, Xeon 80 ff, SD Isotwin Condens F35 E.

Codes that appear on the most Saunier Duval models:
F1 05 06 12 13 02
Just want the most common Saunier Duval problems?
The top 8 faults across the whole Saunier Duval range — causes, DIY checks, repair costs.
Most serious

High-severity Saunier Duval fault codes

F1
Your boiler is attempting to start up, but it is unable to keep the flame alight once it ignites, so it safely shuts itself down.
Themaclassic F24E
 F4
Your boiler is attempting to start its flame but is unable to stay lit, causing it to shut down for safety reasons.
Themaclassic F24E
 Red flashing light
Your boiler has detected a general issue and has entered a safety lockout mode.
Themaclassic F24E
 Flashing pressure
Your boiler has detected that the water pressure level inside the heating system has dropped below the required amount to operate safely.
Themaclassic F24E
 Pictogram of a spark
Your boiler is failing to light the flame, which is likely due to a lack of gas reaching the unit or a problem with the ignition system.
Isomax F30E
All models

22 Saunier Duval boiler models

Themaclassic F24E
Combi Discontinued
4 fault codes · 2008 onwards
Themaclassic Plus F30E
CombiSystem Discontinued
0 fault codes · 1999-2003
Thelia 23E
Combi Discontinued
0 fault codes
Isofast F28E
Combi
0 fault codes · 2001-present
Isomax F30E
Combi Discontinued
16 fault codes · 2002-2007
Ecosy 24E
Combi Discontinued
40 fault codes · 1996-2003
Opalia F24E
Water Heater Discontinued
0 fault codes
Isotwin F30E
Combi Discontinued
0 fault codes · 2003-2010
SD 30e
Combi Discontinued
0 fault codes · 1999-2003
Isofast
Combi Discontinued
30 fault codes · 2000-2010
Sylva
Combi Discontinued
4 fault codes · 1997-2005
Xeon 120 FF
Regular Discontinued
13 fault codes · 1997-2005
Enviroplus
CombiSystem Discontinued
21 fault codes · 2004 onwards
Semia Condens F30 E
Combi Discontinued
4 fault codes
Thema F 30 E Plus
CombiSystem Discontinued
23 fault codes · 2001 onwards
Xeon 30ff
Regular Discontinued
12 fault codes
Themaclassic F35E
Combi Discontinued
20 fault codes · 2003 onwards
Xeon 18 HE
0 fault codes · 2005-present
Xeon Condens 30
0 fault codes · 2005-present
Xeon 40ff
4 fault codes · 2001-present
Xeon 80 ff
4 fault codes · 2001-present
SD Isotwin Condens F35 E
21 fault codes
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