Vaillant
Unstable Power / Firmware Crash
Smart thermostat frequently reboots or restarts by itself, interrupting heating control.
Advertisements
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Advertisements
Possible Causes
Fluctuating low‑voltage supply from boiler, Loose connector on thermostat base, Corrupted firmware, Internal hardware fault on PCB
How to Fix / Troubleshooting
Safety: Isolate mains power before checking wired connections.
- 1. Check mechanical connection: Ensure the thermostat is firmly clipped onto its wall plate and that contacts are clean.
- 2. Verify supply stability: Measure the low‑voltage supply for dips or noise. If unstable, have the boiler or PSU checked by a technician.
- 3. Firmware update: Use the Vaillant app or service menu to update firmware to the latest version.
- 4. Factory reset: Perform a factory reset and reconfigure the system to rule out configuration‑related crashes.
- 5. Replace thermostat: If reboots continue with a stable supply and latest firmware, replace the thermostat.
Advertisements
Repair Difficulty
Medium
3/5
Required Part
Vaillant smart thermostat main PCB
Check Price on Amazon
We may earn a commission from links on this page.
Advertisements