12
VFH InverterFlex
®
- Outdoor Ductless Mini-Split
Heat Controller
VFH InverterFlex System Line Set Requirements
For systems with only one indoor unit, the maximum line set length (Lx) is:
Outdoor Model
Maximum Length (Lx) Max. Elevation Between Outdoor & Indoor Unit (H1)
A-VFH18/24/30 32.8ft (10m)
24.6ft (7.5m)
A-VFH36/42
82ft (25m)
49.2ft (15m)
For systems with more than one indoor unit, the entire system must pass BOTH requirements below.
Maximum Length Requirement based on Indoor Unit Capacity:
Indoor Model Maximum Length
B-VFH09
49.2ft (15m)
B-VFH12
65.6ft (20m)
B-VFH18/24
82ft (25m)
Total Allowable Length based on Outdoor Unit Capacity:
Outdoor Model Zoning Based on Actual Number of Indoor Units Installed
(See Note 2)
Max.
Elevation
Between
Indoor &
Outdoor (H1)
Max. Elevation
Difference
Between each
Indoor Unit
(H2)
Dual Zone
(L1+L2)
Tri-Zone
(L1+L2+L3)
Quad Zone
(L1+L2+L3+L4)
Penta Zone
(L1+L2+L3+L4+L5)
A-VFH18/24/30 98.4ft
(30m)
172.25ft (52.5m)
229.6ft (70m) N/A
24.6 ft (7.5m)
24.6 ft (7.5m)
A-VFH36/42
104.9ft
(32m)
157.5ft (48m)
209.9ft (64m) 262.5ft (80m)
49.2 ft(15m)
Single Zone Example:
An Outdoor A-VFH18 is installed with (1) B-VFH09 indoor unit. The line set must not exceed 32.8ft (10m) and the indoor
unit must not be more that 24.6 ft(7.5m) higher than the outdoor unit.
Multi-Zone Example:
Lx
An outdoor A-V
F
H36 is installed with (1) B-VFH18 and (2) B-VFH09 indoor units. Based on the Indoor requirement, the
18K indoor unit’s line set can’t exceed 82ft (25m) and each 9K indoor units’ line set can’t exceed 49.2ft (15m). This puts
the total system length (L1+L2+L3) at: 82ft (25m) + 49.2ft (15m) + 49.2ft (15m) = 180ft (54.9m). However using the total
allowable length requirement, we see that an A-V
F
H36 Tri-Zone system can’t exceed 157.5ft (48m). Therefore, we
must reduce the line set length to some or all of the indoor units. To ensure that the allowable total length requirement
is met, let’s reduce the line set for the B-VFH18 unit to 75ft (22.9m) and the B-VHF09 units to 40ft (12.2m) each. Now
the total length (L1+L2+L3) requirement is met, as the total = 75ft (22.9m) + 40ft (12.2m) + 40ft (12.2m) = 155ft (47.2m),
which is less than the total allowable length of 157.5ft (48m) for an A-VFH36 Tri-Zone system.
Notes:
1.
The Max. Allowable Elevation H1 and H2 must also be maintained.
2.
The Zoning is based on the actual number of indoor units installed. An outdoor A-VFH42 is capable of having up
to (5) indoor units installed with a max. total line set length of 262.5ft (80m), however if the application is zoned
using only (2) indoor heads, the max. total line set length is reduced to 104.9ft (32m) as the actual application is
a dual zoned system.
Refrigerant Line Set Installation
