Main Boiler Fault Codes

281 fault codes across 18 Main boiler models — explained in plain English.

UK brand owned by Baxi Group. Budget entry-level boilers.

281 fault codes
18 models documented
4 currently sold
14 legacy models

Main fault codes on this site

We document 281 fault codes across 18 Main models, covering 162 distinct codes. Main boilers use a mix of numbered codes and light or status indications. Codes for 13 of these models are taken directly from the manufacturer's own service or installation manual.

Models covered: Eco Elite Combi 25/30, Combi 30 HE, Ecoinstaller 2, Insul 7, System 18 HE, Multipoint FF 3, Combi 24, Eco, Eco Compact System, Eco Elite System, System 18 24 28 HE, System 24 Eco, Eco Compact Combi, MainEco, Eco Elite, 12 Heat ErP range, Combi, System 28 Eco.

Codes that appear on the most Main models:
28 E20 E110 E125 E133 E160
Just want the most common Main problems?
The top 8 faults across the whole Main range — causes, DIY checks, repair costs.
Most serious

High-severity Main fault codes

E20
Your boiler has detected a problem with the sensor that measures the temperature of your heating system, so it has temporarily stopped working to be safe.
Eco Elite Combi 25/30
 E28
Your boiler has detected that the electronic control board currently installed is not the correct model or version specified for your specific appliance.
Eco Elite Combi 25/30
 E50
Your boiler is struggling to accurately measure the temperature of your hot water because a sensor is failing, which usually stops hot water from working properly.
Eco Elite Combi 25/30
 E110
Your boiler has automatically shut down because it detected dangerously high internal temperatures.
Eco Elite Combi 25/30
 E119
Your boiler has temporarily stopped working because the water pressure inside the system has dropped too low.
Eco Elite Combi 25/30
All models

18 Main boiler models

Eco Elite Combi 25/30
Combi Discontinued
8 fault codes · 2012 onwards
Combi 30 HE
Combi Discontinued
12 fault codes · 2005-2012
Ecoinstaller 2
Combi Discontinued
14 fault codes · 2008-2012
Insul 7
Regular Discontinued
8 fault codes
System 18 HE
System Discontinued
9 fault codes · 2006-2011
Multipoint FF 3
Water Heater Discontinued
1 fault codes · 2000-2007
Combi 24
Combi Discontinued
10 fault codes · 2005-2012
Eco
Combi Discontinued
10 fault codes · 2005-2012
Eco Compact System
System
20 fault codes · 2018 onwards
Eco Elite System
System Discontinued
9 fault codes · 2012 onwards
System 18 24 28 HE
System Discontinued
9 fault codes · 2006-2011
System 24 Eco
System Discontinued
9 fault codes · 2008-2012
Eco Compact Combi
Combi
71 fault codes · 2019-present
MainEco
CombiSystem Discontinued
61 fault codes · 2006 onwards
Eco Elite
Combi Discontinued
17 fault codes · 2013-2016
12 Heat ErP range
4 fault codes · 2006-present
Combi
Combi
0 fault codes · 2005-present
System 28 Eco
System Discontinued
9 fault codes · 2008-2012
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