Heat pumps · Error codes · Vaillant
SENSONET-LED-REDVaillant · aroTHERM plus (VWL ../6 A)
SENSONET-LED-RED on a Vaillant aroTHERM plus: Internet connection was disconnected; when connected via LAN: no Internet connection available
Short answer
On a Vaillant heat pump, SENSONET-LED-RED means: Internet connection was disconnected; when connected via LAN: no Internet connection available. The heat pump keeps running.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Internet connection was disconnected; when connected via LAN: no Internet connection available.
Part involved: sensoNET internet gateway.
Likely causes:
- Internet connection was disconnected; when connected via LAN: no Internet connection available.
Is it safe?
| Does the heat pump stop? | No |
|---|---|
| Severity | Information only |
| Engineer needed? | No |
The heat pump keeps running.
Resetting itself: yes - LED changes when connection returns.
Manual reset: not applicable.
What you can check
- Check your broadband router is on and working and that the gateway is powered; restart the router; re-connect the gateway using the myVAILLANT app instructions. Heating continues to run from the room control.
What the engineer will check
- Check router/WLAN or LAN connection and ports (outgoing 443/8443 must be open); re-pair the gateway via the app; check eBUS connection to the system control (F.900 on sensoCOMFORT).
Who to ask for: Homeowner / installer (network); Vaillant app support.
Certification: None.
What you might notice
What owners and engineers report
11 owner and engineer reports mention this.
- App / connectivity problem on the aroTHERM plus (VWL ../6 A): 11 reports
Sources
- sensoNET installation instructions ↗ · 0020285487_05 · page sensoNET 0020285487_05 p.7 (section 4.5) · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026