Viessmann F2: burner fault: the temperature limiter has responded
Checked against Viessmann's own documentation: Viessmann Vitodens 100-W (B1HC/B1KC) installation and service instructions, 5697 787 GB and 2 more sources. Last reviewed October 2026. How we check
Check these first, then call an engineer
The boiler's overheat safety switch (temperature limiter) has tripped, so the burner has gone into a fault state and stays off until it's reset. Viessmann's own fault tables put the system's water level first in the list of checks, then the circulation pump and air in the system.
Recommended pressure when cold for Viessmann boilers: 1.0 to 1.5 bar.
What you can safely do
- Read the pressure gauge with the system cold. If it's below about 1 bar, top up as Viessmann describes: boiler off, wait at least an hour, then fill through the filling loop to 1.5 bar.
- Don't keep resetting it. If F2 comes back, something is stopping the water carrying heat away and an engineer needs to find it.
Call a Gas Safe engineer if
- The pressure is fine and F2 still shows.
- F2 keeps coming back after a reset.
- You've had to top up the pressure more than once or twice this year.
Which Viessmann boilers show F2
| Model | What Viessmann's manual says | Source |
|---|---|---|
| Vitodens 100-W | Burner in a fault state; the temperature limiter has responded. Checks include the water level and the circulation pump. | Viessmann Vitodens 100-W (B1HC/B1KC) installation and service instructions, 5697 787 GB |
| Vitodens 200-W | Fixed high limit switch open. Corrective steps: check the fill level, check the circulation pump, bleed air from the system, then reset. | Viessmann: detailed fault codes for Vitodens 200-W and 222-F (11/2017, North America) |
Why does it trip?
The limiter cuts the burner if the water in the boiler gets too hot. Viessmann's corrective steps point to the water not carrying heat away properly: too little water in the system (low pressure), a circulation pump that isn't working, or air in the system. Checking the pressure is the one part you can safely do yourself. Our pressure checker shows Viessmann's range.
Applies to Viessmann Vitodens 100-W, Viessmann Vitodens 200-W. Codes can differ between models, so check your manual.