This-setting-means-that-additional-heat-can-take-over-operation on a Worcester Bosch Greensource air to water heat pump: Info window: This setting means that additional heat can take over operation
Short answer
On a Worcester Bosch heat pump, This-setting-means-that-additional-heat-can-take-over-operation means: Info window: This setting means that additional heat can take over operation. 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: Info window: This setting means that additional heat can take over operation.
Part involved: additional heat limitation settings.
When it shows: Installer set electric cassette/mixing valve limitation values more than 1 degree below T9 high return temperature.
Likely causes:
- Installer set electric cassette/mixing valve limitation values more than 1 degree below T9 high return temperature.
Is it safe?
| Does the heat pump stop? | Partly |
|---|---|
| Severity | Information only |
| Engineer needed? | Yes |
The heat pump keeps running with some functions stopped.
Resetting itself: yes.
Manual reset: Clears automatically; warnings may be acknowledged.
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
- Select a lower value.
Who to ask for: heat pump installer / controls engineer.
Certification: None specific; electrical isolation required before wiring checks.
What you might notice
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 44 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026