VRF Piping Design Calculator
Calculate refrigerant pipe sizes and equivalent lengths for VRF/VRV systems
Important: Always Refer to Manufacturer Guidelines
This calculator provides general guidance only. VRF/VRV piping requirements vary by manufacturer (Daikin, Mitsubishi, LG, Samsung, etc.). Always use the specific manufacturer's design software and installation manuals for final design and sizing.
System Configuration
kW
Main Line (ODU to First Branch)
m
m
Branch Configuration
m
m
| IDU # | Type | Capacity (kW) | Branch Length (m) | Liquid Line | Gas Line |
|---|
Calculation Results
Main Liquid Line
-
OD (mm)
Main Gas Line
-
OD (mm)
Total Equivalent Length
-
m
Additional Charge
-
kg
System Limits Check
Total Pipe Length:
-
Max Limit:
-
Capacity Ratio:
-
Oil Return:
-
Branch Selector / Refnet Sizing
VRF Piping Guidelines
Typical Pipe Sizes by Capacity
| Capacity Range | Liquid Line (OD) | Gas Line (OD) | Notes |
|---|---|---|---|
| 2.2 - 5.6 kW | φ6.35 (1/4") | φ12.7 (1/2") | Single IDU branch |
| 7.1 - 11.2 kW | φ9.52 (3/8") | φ15.88 (5/8") | Medium capacity |
| 14.0 - 22.4 kW | φ9.52 (3/8") | φ19.05 (3/4") | Sub-header |
| 28 - 45 kW | φ12.7 (1/2") | φ22.2 (7/8") | Main header |
| 50 - 84 kW | φ15.88 (5/8") | φ28.58 (1-1/8") | Large system |
| 100+ kW | φ19.05 (3/4") | φ34.9 (1-3/8") | Multiple ODU |
Typical System Limits
- • Max total pipe length: 165-1000m (varies by model)
- • Max height difference (ODU-IDU): 50-90m
- • Max height difference (IDU-IDU): 15-30m
- • Max single pipe run: 120-165m
- • Equivalent length per elbow: 0.5m
- • Capacity ratio: 50-130% (typical)
Additional Charge Calculation
- • φ6.35 (1/4"): 10 g/m
- • φ9.52 (3/8"): 30 g/m
- • φ12.7 (1/2"): 60 g/m
- • φ15.88 (5/8"): 90 g/m
- • φ19.05 (3/4"): 140 g/m
- • φ22.2 (7/8"): 200 g/m