Heat pumps · Error codes · Lailey and Coates Ltd
E01Lailey and Coates Ltd · Lailey & Coates LCM monobloc (LCM-06/09/17)
E01 on a Lailey and Coates Ltd Lailey & Coates LCM monobloc: Communication failure between outdoor unit and control box
Short answer
On a Lailey and Coates Ltd heat pump, E01 means: Communication failure between outdoor unit and control box. 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: Communication failure between outdoor unit and control box.
Likely causes:
- Wrong communication cable.
- Poor connection between outdoor unit and control box.
- Incoming power cable problem.
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
What you can check
- Read and note the code shown on the controller display, then contact your installer or service engineer.
- Check the heat pump's breaker/isolator at the consumer unit is switched on (do not repeatedly reset if it trips).
What the engineer will check
- Check correct specified communication cable has been used.
- Check connections between outdoor unit and control box.
- Check incoming power cable.
- Check communication cable between controller/PCB/driver board (type, polarity, termination).
- Check power supply to the remote module.
- Replace faulty PCB/controller if wiring is sound.
Who to ask for: heat pump controls / electrical.
Certification: Electrical competence.
What you might notice
Sources
- Lailey & Coates Monobloc Air Source Heat Pumps - Installation & Maintenance Manual (LCM-06 / LCM-09 / LCM-17) ↗ · page 18 (printed; ManualsLib p.19) · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026