Vaillant F.25: what it means and when to call a pro · United Kingdom
Severity: Stop and call a proVaillant gas boiler error F.25. The flue gas temperature is too high, or the flue or air supply is faulty or blocked.
Smell gas? Leave the building and call the gas emergency number: 0800 111 999
Meaning
The flue gas temperature is too high, or the flue or air supply is faulty or blocked.
Severity
Stop and call a pro
Stop. Switch it off and call a pro
Steps are not shown for this code because no qualified person has reviewed them yet. What is safe: switch it off, follow the Do not list and call a pro.
Do not
- Do not keep resetting the boiler.
Source
Official Boiler Fault Codes List, Vaillant
The repair: Boiler flue fault repair
Prices for repairs in United Kingdom are in GBP.
Other Vaillant codes
- Vaillant F.28 The boiler failed to ignite (no flame was detected) and has locked out.
- Vaillant F.29 The flame went out during operation, or the flame sensor signal is faulty.
- Vaillant F.32 The fan is faulty or is not reaching the correct speed.
- Vaillant F.61 The boiler cannot actuate its gas valve, which indicates a fault in the gas valve assembly.
- Vaillant F.63 The memory chip (EEPROM) on the boiler's control board is faulty.
Brands in our catalog for gas boiler: Ariston, Baxi, Bosch, Ferroli, Ideal, Potterton, Vaillant, Viessmann, Worcester Bosch. The same code on another brand is not in the catalog yet, and we do not guess what it means.