T
Tara GrossJul 26, 2025
What to do if the Vaillant VRT 350 Controller display is dark?
- Bbrian13Jul 26, 2025
If the Vaillant Controller's display is dark, it might be due to an appliance fault. Try switching off the mains switch on all heat generators for about 1 minute, then switch them back on. If the display remains dark, inform a qualified technician.