Verified boiler fault code
Keston 53 Fault Code (Heat 2)
Flame loss during operation, with endless restarts activated.
Safety disclaimer
Fault code summary
- Manufacturer
- Keston
- Fault code
- 53
- Fault type
- Flame failure, Ignition
- Severity
- warning
- 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, with endless restarts activated.
What does this fault code mean?
Flame loss during operation, with endless restarts activated.
Common causes
- Flame loss during operation.
Symptoms
- The boiler fault screen shows code 53 and may repeatedly restart.
What can the homeowner safely check?
- Record the code and contact a Gas Safe registered engineer if it repeats.
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
Related fault codes
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Read fault code
Manufacturer documentation
Keston Heat 2 Installation & Servicing ManualFAULT FINDING MENU: Flameloss during operation => endless restarts — code 53.
Last verified
2026-09-12
Frequently asked questions
What does Keston 53 mean?
Flame loss during operation, with endless restarts activated.
Can I reset a Keston 53 fault?
The Heat 2 fault screen shows a Press Reset prompt; do not repeatedly reset an unresolved fault.