Vaillant F.20: what it means and when to call a pro · United States
Severity: Stop and call a proVaillant gas boiler error F.20. The boiler overheated and the safety temperature limiter cut it out. This usually happens when heat cannot escape from the boiler, for example because of closed radiator valves, poor water circulation or a temperature sensor fault.
Smell gas? Leave the building and call the gas emergency number: 911
Meaning
The boiler overheated and the safety temperature limiter cut it out. This usually happens when heat cannot escape from the boiler, for example because of closed radiator valves, poor water circulation or a temperature sensor fault.
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.
Source
Boiler fault codes list, Vaillant
The repair: Boiler overheating repair
Prices for repairs in United States are in USD.
Other Vaillant codes
- Vaillant F.22 The water pressure in the heating system is too low.
- Vaillant F.23 The temperature difference between flow and return is too large, usually because water is not circulating well.
- Vaillant F.24 The boiler temperature is rising too fast, usually because water is not circulating well (air, closed valves or a pump problem).
- Vaillant F.25 The flue gas temperature is too high, or the flue or air supply is faulty or blocked.
- Vaillant F.28 The boiler failed to ignite (no flame was detected) and has locked out.
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.