07 on a Grant Aerona³ R32: Circuit 2 temperature sensor error
Short answer
On a Grant heat pump, 07 means: Circuit 2 temperature sensor error. The heat pump keeps running with some functions stopped. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manuals for this range word it in different ways:
- Circuit 2 temperature sensor error.
- Lower buffer temperature sensor error.
Part involved: wiring-centre temperature sensor.
When it shows: Alert passed from the Smart Controller to the wired room thermostat display; also shown in the Smart Controller alarm list Alert passed from the Smart Controller to the wireless room thermostat display; also shown in the Smart Controller alarm list.
Likely causes:
- Sensor not connected correctly to wiring centre (terminals 38-50, 15V DC).
- Loose connections.
- Sensor damaged or incorrectly installed.
- Sensor configured but not installed per the system scheme.
Is it safe?
| Does the heat pump stop? | Partly |
|---|---|
| Engineer needed? | Yes |
The heat pump keeps running with some functions stopped.
Resetting itself: Not stated.
Manual reset: Not stated.
What you can check
- Note the exact code shown on the controller display and tell your installer or Grant-trained engineer.
- Tap the alarm icon on the Smart Controller touchscreen to view the current alarm list.
What the engineer will check
- Check sensor connections at wiring centre terminals 38-50 (DOC 0203 s12.1.1).
- Check for loose connections at sensor and wiring centre.
- Check sensor installed correctly and undamaged.
- Check sensor configuration matches the installed system scheme.
Who to ask for: Heating controls installer / Grant-trained engineer.
What you might notice
What owners and engineers report
17 owner and engineer reports mention this.
- Insufficient heating (house not warm enough) on the Aerona³ R32: 17 reports
Sources
- Grant Aerona Smart Heat Pump System Controller - Installation & Operating Instructions (UK DOC 0203) ↗ · Rev 2.2 · pages 53, 56 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026