E2X.RLP on a Worcester Bosch Greenstore LECP ground source heat pump: Tripped low pressure switch
Short answer
On a Worcester Bosch heat pump, E2X.RLP means: Tripped low pressure switch. 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: Tripped low pressure switch.
Part involved: low pressure switch.
When it shows: Open contact on low pressure switch (delayed 150 s after compressor start/mode change); compressor stops.
Likely causes:
- Open contact on low pressure switch (delayed 150 s after compressor start/mode change); compressor stops.
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: Acknowledgement required.
What you can check
- Read and note the full alarm text and category letter shown on the controller and pass it to your installer.
- Acknowledge the alarm on the control unit once (the manual allows acknowledgement); if it recurs call the installer.
What the engineer will check
- Diagnose per chapter 21: Open contact on low pressure switch (delayed 150 s after compressor start/mode change); compressor stops.
Who to ask for: ground source heat pump engineer.
Certification: F-gas certification for refrigerant circuit; competent person for electrical work.
What you might notice
Sources
- Installation, Commissioning and Servicing Instructions Worcester Greenstore LECP GSHP (System/Combi 6-11 kW) ↗ · 6 720 806 768 (2013/02) · page 59 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026