Johnson Starley Boiler Fault Codes

262 fault codes across 11 Johnson Starley boiler models — explained in plain English.

Warwick-based UK manufacturer of warm air and water heating systems.

262 fault codes
11 models documented
1 currently sold
10 legacy models

Johnson Starley fault codes on this site

We document 262 fault codes across 11 Johnson Starley models, covering 187 distinct codes. Johnson Starley boilers use a mix of numbered codes and light or status indications. Codes for 10 of these models are taken directly from the manufacturer's own service or installation manual.

Models covered: J32 System ET, C10d, C16d, C16u, C26d, Warmcair DW, Aquair S 10, Aquair S 25, Aquair S, Reno HE, Quantec C.

Codes that appear on the most Johnson Starley models:
13 21 25 26 30 31
Just want the most common Johnson Starley problems?
The top 8 faults across the whole Johnson Starley range — causes, DIY checks, repair costs.
Most serious

High-severity Johnson Starley fault codes

E01
Your boiler has tried to light several times but has been unable to create a flame, meaning you will not have any heating or hot water.
J32 System ET
 F15
Your boiler has stopped working because it has been manually reset too many times in a short window, suggesting an underlying fault that needs professional attention.
J32 System ET
 E03
Your boiler has shut down because it has detected it is getting too hot, which is a safety feature to prevent damage.
J32 System ET
 F37
Your boiler has stopped working because the water pressure in the central heating system has dropped too low.
J32 System ET
 F40
Your boiler has detected that the water pressure in the central heating system is too low or too high for it to operate safely.
J32 System ET
All models

11 Johnson Starley boiler models

J32 System ET
System Discontinued
22 fault codes · 1994-2005
C10d
Regular Discontinued
14 fault codes · 2001-2007
C16d
Regular Discontinued
13 fault codes · 2006-2009
C16u
Regular Discontinued
14 fault codes · 1994-2003
C26d
Combi Discontinued
14 fault codes · 2007-2011
Warmcair DW
Regular
38 fault codes · 2012-present
Aquair S 10
Heat Interface Unit Discontinued
93 fault codes
Aquair S 25
Heat Interface Unit Discontinued
0 fault codes
Aquair S
Heat Interface Unit Discontinued
0 fault codes
Reno HE
CombiSystem Discontinued
23 fault codes · 2005 onwards
Quantec C
CombiSystem Discontinued
31 fault codes · 2012 onwards
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