R-Pro › Field cases › VRF systems
VRF Branch Pipe Design — Equivalent Length and Pipe Sizing
Likely causes
Main / branch equivalent length and pipe size
Check: Main length = outdoor to first branch. Branch length = each branch to next branch or indoor unit. Total equivalent length = actual + 0.5–1 m per branch/bend. Pipe size per outdoor capacity (Daikin/Mitsubishi/LG manual tables). Gas pipe > Liquid > Equalizing (3-pipe simultaneous heating/cooling).
What to do: Design with manufacturer software (Daikin Reflex, Mitsubishi MELANS-CALC, LG ATW). Drawing must show each branch location + equivalent length + pipe size. At commissioning, run all indoor units simultaneously and verify balanced distribution. Exceeding limits = compressor protection trips + 30% capacity loss.
VRF design = use manufacturer-specific software (Daikin Reflex / Mitsubishi MELANS-CALC / LG ATW). Installation inspection = photograph each branch location. Exceeding limits = compressor protection trips + capacity drop 30%+. Branch kits = same brand and model line only.
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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