5481 on a Worcester Bosch Bosch Compress 5800i Hybrid Heat Pump: No CAN communication between hybrid manager and outdoor unit
Short answer
On a Worcester Bosch heat pump, 5481 means: No CAN communication between hybrid manager and outdoor unit. 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: No CAN communication between hybrid manager and outdoor unit.
Part involved: CAN BUS hybrid manager - outdoor unit.
When it shows: No CAN communication between hybrid manager and outdoor unit.
Likely causes:
- CAN BUS cable continuity/wire connection.
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 removed.
Manual reset: Manual 12.1: fault indications can be reset on the control unit in the diagnostic menu with Reset.
What you can check
- Read and note the full code (and sub-code) shown on the controller and pass it to your installer.
- If the hybrid system stops using the heat pump, the gas boiler may still provide heat - do not attempt repairs yourself.
What the engineer will check
- Check cable continuity and wiring; replace cable.
Who to ask for: heat pump installer / electrician.
Certification: Electrical work to BS 7671 by competent person.
What you might notice
Sources
- Installation/operating instructions Hybrid-Set CSH5800iAW O ↗ · 6721875003 (2024/08) · page 41 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026