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Boiler fault codes
What the code on your boiler display means, and what you can safely try before calling an engineer.
Vaillant fault codes
ecoTEC plus, ecoTEC pro, ecoTEC sustain and ecoFIT pure
See 8 common codesWorcester Bosch fault codes
Greenstar i, Ri, Si Compact, CDi Compact, 2000, 4000 and 8000
See 8 common codesIdeal fault codes
Logic, Logic+, Logic Max, Vogue and i-mini
See 9 common codesBaxi fault codes
Baxi 200, 400, 600, 800 and Assure
See 8 common codesBefore you look up a code
- Write the code down exactly as it appears, including any letters.
- Check the pressure gauge. Low pressure causes more lockouts than anything else.
- Check your gas supply: does the hob work, and does your meter have credit?
- In freezing weather, check the condensate pipe outside. See our frozen condensate pipe guide.
- Reset the boiler once. If the same code comes back, stop and book a repair.
Safety first. Never take the casing off your boiler. Only a Gas Safe registered engineer should work inside it. If you smell gas, call 0800 111 999.
Codes that mean stop and call
Some codes point to faults that should not be reset over and over: false flame, flue faults, gas valve faults and repeated overheating. If you see one of these, switch the boiler off and book a repair visit.
Do not see your make?
We repair all the main makes, including Glow-worm, Viessmann, Potterton, Alpha, Intergas and Ariston. Tell us the code when you book and the engineer will come prepared.