Error code
ERROR F99 F99 fault code
How it shows on the unit TIMER indicator blinking; no numeric blink count specified
Applies to 4 models
CS-VZ9SKE, CS-VZ12SKE, CU-VZ9SKE, CU-VZ12SKE
What this means
The unit has stopped and reports ERROR F99. The manual does not define the underlying fault for consumers; this is not a no-error or no-fault status.
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.
Using Claude Code or Meta Muse? Connect HeatPump AI and ask it about ERROR F99.