Nest thermostat: W5: can’t connect to Wi-Fi (possible hardware fault)
The thermostat can’t connect to Wi-Fi. Google says this can indicate a hardware malfunction, and the thermostat may need to be replaced.
Applies to: Nest thermostats with a ring and Quick View menu. What you see: a code and words.
What Google says to do
- Check on the thermostat itself (the code does not appear in the app): press the ring, choose Settings, turn to Network. “Error - nest.com/w5” is the W5 code; your network name or “Not connected” is not.
- Restart the thermostat: press the ring, go to Settings, Reset, Restart. Your settings are kept. Then reconnect under Settings, Network.
- If the restart does not clear W5, contact Google Nest customer support about replacement, with the help code and the serial number ready (it is above the QR code on the back of the display).
The maker puts this down to Wi-Fi or the network. If the problem is the router itself, its own lights are explained on the router and broadband hub lights page.
Source
Google’s own help page, read on the date shown.
- Google Nest Help: Troubleshoot a Nest thermostat W5 code — Nest thermostats with a ring (Quick View menu). support.google.com Checked 2026-09-29.