Heat pumps · Error codes · Aira
THERMOSTAT-DISCONNECTEDAira · Heat Pump (Aira Outdoor Unit)
THERMOSTAT-DISCONNECTED on an Aira Heat Pump: The thermostat has either failed to connect to the heat pump or has lost its connection
Short answer
On an Aira heat pump, THERMOSTAT-DISCONNECTED means: The thermostat has either failed to connect to the heat pump or has lost its connection. The heat pump keeps running.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: The thermostat has either failed to connect to the heat pump or has lost its connection.
Part involved: Aira Room Thermostat (Thread).
Likely causes:
- Out of Thread range (~25 m, walls reduce), batteries.
Is it safe?
| Does the heat pump stop? | No |
|---|---|
| Severity | Warning |
| Engineer needed? | No |
The heat pump keeps running.
Resetting itself: yes.
Manual reset: battery-removal reset.
What you can check
- Take the thermostat off its wall mount, hold it in front of the indoor unit and wait for it to reconnect; if it fails, remove the 3x AAA batteries for at least 20 s and reinsert; then return it to its wall mount.
What the engineer will check
- Re-commission thermostat.
Who to ask for: Aira-employed Clean Energy Technician (R290 heat pump).
Certification: Aira-trained/licensed technician; R290 flammable refrigerant competence for refrigerant work.
What you might notice
Sources
- Get to know your Aira Heat Pump system (homeowner guide, UK) ↗ · UK homeowner guide · page ManualsLib p.11 (printed pp.20-21) · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026