Verified boiler fault code
Keston 57 Fault Code (Heat 2)
False flame with a heat demand.
Safety disclaimer
Fault code summary
- Manufacturer
- Keston
- Fault code
- 57
- Fault type
- Flame detection, 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
False flame with a heat demand.
What does this fault code mean?
False flame with a heat demand.
Common causes
- False flame with heat demand.
Symptoms
- The boiler fault screen shows code 57 and a lockout condition.
What can the homeowner safely check?
- Record the code and contact a qualified 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 and gas-valve shut-off.
Applicable boiler models
Related fault codes
- 1 — Heat 2
Flow thermistor open circuit (blocking).
Read fault code - 10 — Heat 2
Water-pressure sensor defect.
Read fault code - 11 — Heat 2
Flow thermistor open circuit; lockout after 24 hours.
Read fault code - 12 — Heat 2
Flow thermistor short circuit; lockout after 24 hours.
Read fault code - 13 — Heat 2
Return thermistor open circuit; lockout after 24 hours.
Read fault code - 14 — Heat 2
Return thermistor short circuit; lockout after 24 hours.
Read fault code - 19 — Heat 2
Heat thermistor open circuit (blocking).
Read fault code - 2 — Heat 2
Flow thermistor short circuit (blocking).
Read fault code
Manufacturer documentation
Keston Heat 2 Installation & Servicing ManualFAULT FINDING MENU: False flame (with heat demand) — code 57.
Last verified
2026-09-12
Frequently asked questions
What does Keston 57 mean?
False flame with a heat demand.
Can I reset a Keston 57 fault?
The Heat 2 fault screen shows a Press Reset prompt; do not repeatedly reset an unresolved fault.