Verified boiler fault code
Keston 54 Fault Code (Heat 2)
Flame loss during operation, progressing to lockout after restart attempts are used.
Safety disclaimer
Fault code summary
- Manufacturer
- Keston
- Fault code
- 54
- Fault type
- Flame failure, Safety lockout
- Severity
- lockout
- Reset
- The Heat 2 fault screen shows a Press Reset prompt; do not repeatedly reset an unresolved fault.
- Applicable models
- Keston Heat 2 45, Keston Heat 2 55, Keston Heat 2 45P, Keston Heat 2 55P
Quick answer
Flame loss during operation, progressing to lockout after restart attempts are used.
What does this fault code mean?
Flame loss during operation, progressing to lockout after restart attempts are used.
Common causes
- Flame loss during operation.
Symptoms
- The boiler fault screen shows code 54 and may lock out.
What can the homeowner safely check?
- Record the code and contact a Gas Safe registered engineer.
Boiler reset information
The Heat 2 fault screen shows a Press Reset prompt; do not repeatedly reset an unresolved fault.
When should I call an engineer?
Contact a suitably qualified heating engineer when the fault persists, the boiler locks out, or the manufacturer instructions do not resolve it. For gas appliance work in the UK, use a Gas Safe registered engineer.
Engineer diagnosis
- Investigate flame detection, gas supply, combustion and condensate/flue condition.
Applicable boiler models
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Manufacturer documentation
Keston Heat 2 Installation & Servicing ManualFAULT FINDING MENU: Flameloss during operation => Lockout after restart attempts are used — code 54.
Last verified
2026-09-12
Frequently asked questions
What does Keston 54 mean?
Flame loss during operation, progressing to lockout after restart attempts are used.
Can I reset a Keston 54 fault?
The Heat 2 fault screen shows a Press Reset prompt; do not repeatedly reset an unresolved fault.