Error code
Unknown HP box alarm Heat-pump box identification fault
Applies to 3 models
RXC35, RXC50, RXC65
What this means
The controller cannot identify the heat-pump box, likely because of poor electrical contact or incorrect wiring.
When to call a technician
This fault involves refrigerant, pressure, or electrical work that must be handled by a certified technician under EU F-gas rules. Do not attempt to open the refrigerant circuit, access mains wiring, or adjust pressure components yourself. Contact a qualified installer or servicer for this one.
See the official ComfortZone manualA deep link to the manufacturer's own PDF for full technical detail. We link to manuals, we never host them.