How to resolve Bluestar VRV/VRF outdoor unit C4,C6,C9 errors? A/C Blog HVAC VRV/VRF How to resolve Bluestar VRV/VRF outdoor unit C4,C6,C9 errors? Admin September 17, 2024 If your office premises and company uses VRF/VRV of blue start unit you may have seen these... Learn more Read more about How to resolve Bluestar VRV/VRF outdoor unit C4,C6,C9 errors?