Error code
21 High temperature, high pressure, or intermittent communication fault
Applies to 4 models
RAS-25PKVSG-ND, RAS-35PKVSG-ND, RAS-25PAVSG-ND, RAS-35PAVSG-ND
What this means
The outdoor return signal stopped after startup, with possible TE/TC high temperature, protector operation, high pressure, refrigerant, or signal-circuit causes.
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.