Is-the-heat-pump-fused-for-this-output on a Worcester Bosch heat pump: Warning window: Is the heat pump fused for this output?
Short answer
On a Worcester Bosch heat pump, Is-the-heat-pump-fused-for-this-output means: Warning window: Is the heat pump fused for this output? The heat pump keeps running. An engineer is needed to fix the cause. The wording differs by model range — each is shown below.
Reviewed 23 September 2026 · 2 sources
What it means
On the Greensource air to water heat pump (monobloc with HWDU)
The manual says: Warning window: Is the heat pump fused for this output?
Part involved: fuse sizing.
When it shows: Warning to confirm heat pump fuse rating matches output.
Likely causes:
- Warning to confirm heat pump fuse rating matches output.
On the Greensource Split HP Hydrolight / Hydrocomfort
The manual says: Warning: Is the heat pump fused for this output?
Part involved: fuse sizing.
When it shows: Confirms system is fused for the load ('Check fuse' in info log).
Likely causes:
- Confirms system is fused for the load ('Check fuse' in info log).
Is it safe?
On the Greensource air to water heat pump (monobloc with HWDU)
| Does the heat pump stop? | No |
|---|---|
| Severity | Warning |
| Engineer needed? | Yes |
The heat pump keeps running.
Resetting itself: yes.
Manual reset: Clears automatically; warnings may be acknowledged.
On the Greensource Split HP Hydrolight / Hydrocomfort
| Does the heat pump stop? | No |
|---|---|
| Severity | Warning |
| Engineer needed? | Yes |
The heat pump keeps running.
Resetting itself: yes.
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.
What the engineer will check
On the Greensource air to water heat pump (monobloc with HWDU)
- Confirm fuse sizing.
Who to ask for: heat pump installer / electrician.
Certification: Electrical work to BS 7671 by competent person.
On the Greensource Split HP Hydrolight / Hydrocomfort
- Check outdoor and Hydrolight/Hydrocomfort fuse sizes.
Who to ask for: heat pump installer / electrician.
Certification: Electrical work to BS 7671 by competent person.
Sources
- Installation Manual Air to Water Heat Pump with DHW distribution unit Greensource 6/7/9.5 kW ↗ · 6 720 641 467 (2010/01) · page 40 · Reviewed 23 September 2026
- Installation, Commissioning and Servicing Instructions Greensource Hydrolight and Hydrocomfort (ODU 7.5-12) ↗ · 6 720 806 629 (2013/02) · page 66 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026