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Boiler Error Code Knowledge Hub

Free troubleshooting guides for all major UK boiler brands. Find out what your error code means and whether you can fix it yourself.

Select Your Boiler Brand

Boiler Error Code Guides

Choose your boiler manufacturer below to find detailed troubleshooting guides for every error code

Vaillant Boiler Codes

ecoTEC, ecoFIT, turboTEC series

Most Common Codes

F22 F28 F29 F75
View All Vaillant Codes

Worcester Bosch Codes

Greenstar, CDi, Si series

Most Common Codes

EA E9 H07 C6
View All Worcester Codes

Baxi Boiler Codes

Duo-tec, Platinum, 800 series

Most Common Codes

E119 E133 E110 E125
View All Baxi Codes

Ideal Boiler Codes

Logic, Vogue, Mexico series

Most Common Codes

F1 L2 L9 FD
View All Ideal Codes

Glow Worm Codes

Energy, Ultimate, Betacom series

Most Common Codes

F1 F22 F28 F75
View All Glow Worm Codes

Viessmann Codes

Vitodens, Vitoladens series

Most Common Codes

F4 F5 0C A0
View All Viessmann Codes

Potterton Codes

Assure, Titanium, Promax series

Most Common Codes

E119 E133 E110 E125
View All Potterton Codes

Alpha Boiler Codes

E-TEC, Evoke, CD series

Most Common Codes

E10 E28 E34 E53
View All Alpha Codes

Main Boiler Codes

Eco Compact, System, Combi series

Most Common Codes

E119 E133 E110 E168
View All Main Codes

Ferroli Boiler Codes

Modena, Optimax, Domicondens series

Most Common Codes

A01 A03 A06 F04
View All Ferroli Codes

Ravenheat Codes

CSI, RSF, WH series

Most Common Codes

01 03 04 05
View All Ravenheat Codes

Biasi Boiler Codes

Advance, Riva, Inovia series

Most Common Codes

AL01 AL03 AL06 AL10
View All Biasi Codes
Quick Help

Common Boiler Problems

Not sure what's wrong? Here are the most common boiler issues we see

Low Boiler Pressure

Pressure gauge in the red zone? This is usually an easy DIY fix. Find step-by-step instructions for your boiler brand.

No Hot Water

Boiler working but no hot water? Could be the diverter valve, thermostat, or a simple setting issue.

Boiler Won't Ignite

Error codes like F28 or EA? In winter this is often a frozen condensate pipe - we show you how to thaw it safely.

Boiler Keeps Locking Out

Repeated lockouts indicate an underlying problem. Find out what's causing it before you keep resetting.

Important Gas Safety Information

While some boiler issues can be safely fixed by homeowners, gas work must only be carried out by a Gas Safe registered engineer. Never attempt to:

  • Open the boiler casing to access internal components
  • Work on gas supply pipes or the gas valve
  • Disassemble or repair the flue system
  • Bypass any safety mechanisms

If you smell gas: Leave the property immediately, don't use any electrical switches, and call the National Gas Emergency Service on 0800 111 999

Need a Gas Safe Engineer?

If your boiler needs professional attention, our Gas Safe registered engineers are here to help. Available 24/7 for emergencies across Harrow, London and surrounding areas.

Book an Engineer Call 0203 151 0881
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