R-Pro › Field cases › Air conditioning
VRF/Multi System — One Indoor Not Working (Addressing/Comm)
Likely causes
Address conflict / comm break / indoor PCB
Check: 1 of 8 multi indoors not responding or in error. Main controller doesn't show that unit. LG CH200/203, Samsung E101/E198. Check: ① Indoor DIP switch (address 0-15, no duplicate). ② Comm line H1/H2 (~100Ω, ∞=break, 0Ω=short). ③ Indoor PCB LED (normal = 1Hz blink). ④ Outdoor main board recognition list (service mode).
What to do: On address duplication, reset each unit per manual → run Auto Address from outdoor main board. Comm break: replace with new twisted pair (failed cable / corroded terminals), use crimp lugs. Inspect entry terminal looseness and branch junctions. Indoor PCB replacement requires exact model code (no compatibles). Comm length limit: LG/Samsung ≤1000m, daisy-chain recommended.
VRF address starts from 1, not 0 (LG/Samsung manual). On first install, technicians often forget to dial address → no auto-fill. Recommended to pump down then replace board (prevents current conflict). Don't run comm line in same conduit as 220V (induces noise). Industrial single controller ≈ ₩500-800k.
All 565 cases work offline in R-Pro, with error codes for 62 brands and P-T data for 108 refrigerants.
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