22
VFH InverterFlex
®
- Outdoor Ductless Mini-Split
Heat Controller
Field Charging Example
36KBTU/H
Outdoor Unit
Four 9KBTU/H
Indoor Units
OUTDOOR UNIT
INDOOR UNIT
LINE SET/LENGTH
36KBTU/H
j
9KBTU/H
a / 30 ft (9m)
k
9KBTU/H
b / 35 ft (10.6m)
l
9KBTU/H
c / 40 ft (12.2m)
m
9KBTU/H
c / 50 ft (15.2m)
The allowable line length for a 36KBTU/H unit is
131 ft (40m) as shown on the table on page 17.
The total line set length for the example installation
is 154 ft (47m) which is greater than the allowable
length, so additional refrigerant is required.
To calculate the additional refrigerant needed ,
multiply the additional line length by .024 oz/ft
(20g/m) for a 36KBTU/H unit. To get the additional
line length, subtract the allowable line length from
the total system line length.
Total length of refrigerant line set = a + b + c + d
= 30' (9m)+ 35' (10.6m) + 40’ (12.2m) + 49' (15.2m)
=
154 ft (47m) total
CALCULATION EXAMPLE:
Total system line length 154 ft (47m) minus the
allowable line length 131 ft (40m) = 23 ft (7m)
To determine the additional refrigerant, the additional
line length 23 ft (7m) is multiplied by 0.24 oz/ft
(20g/m) = 5.5 oz (154g)
In this example, 5.5 oz (156g) of additional refrigerant
is needed for a complete charge.
