Verified boiler fault code
Biasi E25 Fault Code (BASICA COND)
Boiler in antifreeze mode.
Safety disclaimer
Fault code summary
- Manufacturer
- Biasi
- Fault code
- E25
- Fault type
- Other manufacturer-specific faults, Central heating
- Severity
- medium
- Reset
- The display indicates antifreeze operation; allow the manufacturer protection cycle to operate and seek advice if the code persists.
- Applicable models
- BASICA COND 24C, BASICA COND 28C, BASICA COND 32C
Quick answer
Boiler in antifreeze mode.
What does this fault code mean?
Boiler in antifreeze mode.
Common causes
- Antifreeze protection active
Symptoms
- E25 shown on the LCD
- Boiler in antifreeze phase
What can the homeowner safely check?
- Check that the boiler has power and that external controls have not been switched off; do not block the condensate outlet.
Boiler reset information
The display indicates antifreeze operation; allow the manufacturer protection cycle to operate and seek advice if the code persists.
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
- A qualified engineer should investigate if antifreeze mode does not clear or if the appliance cannot maintain safe temperature.
Applicable boiler models
Related fault codes
- E01 — BASICA COND
Safety lockout due to failed ignition.
Read fault code - E02 — BASICA COND
Lockout due to the safety thermostat.
Read fault code - E03 — BASICA COND
EEPROM error.
Read fault code - E04 — BASICA COND
Pump circulation failure or insufficient system pressure.
Read fault code - E05 — BASICA COND
Fan-control anomaly.
Read fault code - E06 — BASICA COND
Heating NTC probe failure.
Read fault code - E07 — BASICA COND
DHW NTC probe failure.
Read fault code - E08 — BASICA COND
External NTC probe failure.
Read fault code
Manufacturer documentation
Biasi BASICA COND user manual and installation instructionsSIGNAL DISPLAYED BY THE LCD: | E25+ | Boiler in antifreeze |
Last verified
2026-09-12
Frequently asked questions
What does Biasi E25 mean?
Boiler in antifreeze mode.
Can I reset a Biasi E25 fault?
The display indicates antifreeze operation; allow the manufacturer protection cycle to operate and seek advice if the code persists.