R-Pro › Field cases › VRF systems
VRF Y-Joint Installation — Horizontal / Inclination Rules
Likely causes
Y-joint orientation + inclination rules
Check: Install Y-joint within ±15° of horizontal (per manufacturer mark). Never install vertically (oil trapping, uneven distribution). Provide 3 m straight pipe after branch (flow stabilization). First 90° bend = ≥0.5 m from branch. Use only certified insulated branch kits.
What to do: Install Y-joint within ±15° of horizontal, following manufacturer orientation mark. Maintain 3 m straight pipe after branch before first 90° bend. Use only manufacturer-certified branch kits (with insulation). Test = run all indoor units simultaneously and verify discharge temperature consistency (±2°C).
Y-joint defects = VRF distribution imbalance → some indoor units underperform. Test = run all indoor units simultaneously and verify consistent discharge temperatures. Counterfeit kits lack flammability safety certification for R-32/R-454B = leak risk.
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