Error-in-room-sensor-board-or-error-in-E12-T5-room-sensor-board on a Worcester Bosch Greensource Split HP Hydrolight / Hydrocomfort: Alarm: Error in room sensor board or error in E12.T5 room sensor board
Short answer
On a Worcester Bosch heat pump, Error-in-room-sensor-board-or-error-in-E12-T5-room-sensor-board means: Alarm: Error in room sensor board or error in E12.T5 room sensor board. The heat pump stops until the fault clears or is reset. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Alarm: Error in room sensor board or error in E12.T5 room sensor board.
Part involved: CAN-BUS room controller.
When it shows: Fault in CAN-BUS room controller or its communication.
Likely causes:
- Fault in CAN-BUS room controller or its communication.
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Severity | Fault — needs a manual reset once the cause is fixed |
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
Resetting itself: no.
Manual reset: Acknowledge by pressing the rotary selector (Acknowledge) on the Hydrolight/Hydrocomfort user interface.
What you can check
- Read and note the full alarm text shown on the controller and pass it to your installer.
- Acknowledge the alarm once on the control panel; if it returns, call the installer.
What the engineer will check
- Check terminations, 12 V DC supply; replace room controller.
Who to ask for: heat pump installer / controls engineer.
Certification: None specific; electrical isolation required before wiring checks.
What you might notice
Sources
- Installation, Commissioning and Servicing Instructions Greensource Hydrolight and Hydrocomfort (ODU 7.5-12) ↗ · 6 720 806 629 (2013/02) · page 65 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026