U8
Mitsubishi · MSZ-FS06NA 6,000 BTU Compact Wall-Mount Indoor Unit
When multiple wired remote controllers are connected to a single indoor unit (main and sub controllers), communication between them has failed. Check the daisy-chain wiring between controllers. Verify each controller is set to the correct main/sub designation. This is uncommon in residential installations.
Error U8 on the Mitsubishi MSZ-FS06NA 6,000 BTU Compact Wall-Mount Indoor Unit means: Main/Sub Remote Controller Communication Error. The top-ranked community fix is “Replace Remote Controller Communication Interface Board” (medium difficulty, ~45 min, DIY cost: $15-$25). 2 community-ranked fixes available below.
Published February 2026 · 2 fixes · mini split
Content is based on manufacturer service documentation, community repair experience, and OEM technical bulletins. Always verify with your owner's manual.Learn about our editorial standards.
While many mini split repairs can be done safely at home, consider hiring a qualified technician if:
Average professional repair cost for this issue: $180-$300.
mini_split · 2 fixes
mini_split · 2 fixes
mini_split · 2 fixes
mini_split · 2 fixes
mini_split · 2 fixes
heat_pump · 2 fixes
mini_split · 2 fixes
heat_pump · 2 fixes
heat_pump · 2 fixes
heat_pump · 2 fixes
mini_split · 2 fixes
mini_split · 2 fixes
heat_pump · 2 fixes
mini_split · 2 fixes
Remote Controller PCB Error
Remote Controller Signal Receiving Error
Remote Controller Communication Error
Indoor Unit PCB Processor Error
Indoor/Outdoor Communication Error (Legacy)
Indoor Unit EEPROM Error
Indoor Fan Motor Error
Indoor Unit Overcurrent Protection
The Mitsubishi MSZ-FS06NA 6,000 BTU Compact Wall-Mount Indoor Unit has 8 other known error codes:
Error code U8 also appears on 14 other Mitsubishi models:
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