Heat pumps · Error codes · Octopus Energy
HUB-FLASHING-REDOctopus Energy · Cosy (Cosy Octopus heat pump)
HUB-FLASHING-RED on an Octopus Energy Cosy: Cosy Heat Pump has a fault
Short answer
On an Octopus Energy heat pump, HUB-FLASHING-RED means: Cosy Heat Pump has a fault. The manual does not say whether the heat pump stops. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Cosy Heat Pump has a fault.
Part involved: Cosy heat pump outdoor unit / Cosy Hub reporting.
Likely causes:
- Not specified by manufacturer; any heat-pump fault (Octopus names protections: high pressure switch, refrigerant temperature sensor, blocked evaporator sensor, water flow sensor, fan tachometer, sensor failure -> safe error state).
Is it safe?
| Does the heat pump stop? | Not stated |
|---|---|
| Engineer needed? | Yes |
The manual does not say whether the heat pump stops.
Resetting itself: unknown.
Manual reset: unknown.
What you can check
- Note the Hub light and any message in the Octopus app; check the heat pump supply breaker/isolator is on; check the outdoor unit is not blocked by leaves, debris or snow (brush away gently, do not touch the fins); then contact Octopus.
What the engineer will check
- Remote fault read by Octopus; on-site inspection of heat pump protections (HP switch, flow sensor/filter, refrigerant sensors, fan), Modbus link Hub-heat pump, electrical supply.
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.25 (printed 24) · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026