5483 on a Worcester Bosch Bosch Compress 5800i Hybrid Heat Pump: Signal from ret. temp. sensor TH1 on hybr. man. outside curve
Short answer
On a Worcester Bosch heat pump, 5483 means: Signal from ret. temp. sensor TH1 on hybr. man. outside curve. 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: Signal from ret. temp. sensor TH1 on hybr. man. outside curve.
Part involved: TH1 temperature sensor.
When it shows: Signal from ret. temp. sensor TH1 on hybr. man. outside curve.
Likely causes:
- Cable break; sensor defective.
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 sensor cable and sensor; renew sensor.
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