Indoor unit displays F0 and the unit may not cool or heat properly.

Safety first: Turn off power. Do not attempt to charge or recover refrigerant without proper certification and equipment.

• Visual leak check: Inspect all accessible copper joints and flare nuts for oil stains or greenish corrosion. Tighten slightly if obviously loose, but do not overtighten.
• Check mounting and supports: Ensure copper lines are not rubbing against sharp metal edges or being crushed by brackets.
• Do not continue running: Avoid operating the unit for long periods with F0 active, as low refrigerant can overheat the compressor.
• Professional repair: A licensed technician must locate the leak (using nitrogen, soap solution, or electronic detector), repair it, evacuate the system, and recharge with the exact Haier-specified refrigerant amount.