The 050-W has a black screen with buttons along the bottom. Later 100-W boilers can look the same — if yours has no knobs, use these steps.
- Tap the menu button until the heating temperature is on the screen. In constant operation this is the flow; with weather compensation it may show room temperature instead.
- Press down to lower it, or up to raise it, then press OK.
- Stop around 55°C if the house still warms. The factory standard flow is 60°C. If a room thermostat or OpenTherm controller is fitted, set that as well.
Look up your exact model on Boiler Manuals if the fascia does not match. Then return to the Viessmann flow-temperature page or the Boiler Optimiser.