Heat pumps · Error codes · Octopus Energy
HUB-SOLID-YELLOWOctopus Energy · Cosy (Cosy Octopus heat pump)
HUB-SOLID-YELLOW on an Octopus Energy Cosy: Lost Wi-Fi connection
Short answer
On an Octopus Energy heat pump, HUB-SOLID-YELLOW means: Lost Wi-Fi connection. The heat pump keeps running.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Lost Wi-Fi connection.
Part involved: Cosy Hub Wi-Fi / home router.
Likely causes:
- Home router off or not working; Wi-Fi change.
Is it safe?
| Does the heat pump stop? | No |
|---|---|
| Severity | Warning |
| Engineer needed? | No |
The heat pump keeps running.
Resetting itself: yes (Hub automatically tries to reconnect).
Manual reset: no.
What you can check
- Make sure the Wi-Fi router is switched on and working; the Hub should reconnect automatically. Heating/hot water mode can still be changed with the Hub buttons.
What the engineer will check
- Re-provision Hub Wi-Fi if credentials changed.
Who to ask for: Manufacturer-employed engineer (Octopus Energy Services) - R290/ heat pump.
Certification: Octopus-authorised engineer; F-gas/ R290 flammable refrigerant competence for refrigerant work.
What you might notice
Sources
- Get to know your Cosy heat pump (user guide) v20.2 ↗ · 20.2 (file: Get_to_know_your_Cosy-20.2-internal.pdf) · page PDF p.16 (printed 15); troubleshooting PDF p.24 (printed 23) · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026