Error code
UA-00 Indoor/outdoor unit mismatch or signal-transmission fault
Applies to 25 models
CTXM15R2V1B, CTXM15R5V1B, FTXM20R2V1B, FTXM20R5V1B, FTXM25R2V1B, FTXM25R5V1B, FTXM35R2V1B, FTXM35R5V1B, FTXM42R2V1B, FTXM42R5V1B, FTXM50R2V1B, FTXM60R2V1B, FTXM71R2V1B, ATXM20R2V1B, ATXM20R5V1B, ATXM25R2V1B, ATXM25R5V1B, ATXM35R2V1B, ATXM35R5V1B, ATXM50R2V1B, RXM20~71R(9), ARXM25~71R(9), FTXM20~71R, ATXM25~50R, FVXM25~50A
What this means
Signal transmission is abnormal or the indoor and outdoor units are an incompatible combination.
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 Daikin manualA deep link to the manufacturer's own PDF for full technical detail. We link to manuals, we never host them.