A11-3091 on a Worcester Bosch heat pump: Room temperature sensor defective (3091 = heating circuit 1...3094 = heating circuit 4)
Short answer
On a Worcester Bosch heat pump, A11-3091 means: Room temperature sensor defective (3091 = heating circuit 1...3094 = heating circuit 4). 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 manual says: Room temperature sensor defective (3091 = heating circuit 1...3094 = heating circuit 4).
Part involved: room temperature sensor (controller/remote).
When it shows: Room temperature sensor defective (3091 = heating circuit 1...3094 = heating circuit 4).
Likely causes:
- Defective room temperature sensor in system controller or remote control.
Is it safe?
| Does the heat pump stop? | Partly |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
| Engineer needed? | Yes |
The heat pump keeps running with some functions stopped.
Resetting itself: Clears when cause is removed.
Manual reset: User guides (7001i/7400i AWE, 3400i AWS, section 3.5): user may confirm the fault by pressing the selector; if it persists call the contractor with fault code, sub-code and user-interface ID no.
What you can check
- Read and note the full code (and sub-code) shown on the controller and pass it to your installer.
- Confirm/acknowledge the fault once at the controller (press selector) as the user guide allows; if it returns, call the installer.
What the engineer will check
- Change control type to weather-compensated and frost protection to outside-temperature dependent if necessary; replace system controller or remote control.
Who to ask for: heat pump installer / controls engineer.
Certification: None specific; electrical isolation required before wiring checks.
What you might notice
Sources
- Installation instructions User interface HPC 410 ↗ · 6721832682 (2021/02) · page 18 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026