Error code
H3-00 High-pressure switch malfunction
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
The high-pressure switch is active while the compressor is off.
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.