Airwell OU-PSINV-70TH Installation Instructions Manual page 10

Table 1-7 Connection Tube Sizes (Twin, Triple, Double-Twin)
Type capacity of indoor unit
Gas tube
Liquid tube
Amount of additional charge per 1 m
Charge with the amount of additional refrigerant calculated using the formula below, based on the values in Table 1-7 and the size and
length of the liquid tubing.
Amount of additional refrigerant charge (g)
Do not remove refrigerant from the system, even if the result of the calculation is negative.
Additional refrigerant amount (g) = Additional refrigerant for main tubing (g) + Additional refrigerant for distribution tubing (g)
Additional refrigerant amount (g) = Additional refrigerant for main tubing (g) + Additional refrigerant for distribution tubing (g)
(Use with the current refrigerant charge.)
(a) Actual length (m) of main tubing (ø9.52)
Actual length (m) of main tubing (ø12.7)
(b) Total length of distribution tubing (ø9.52)
(c) Total length of distribution tubing (ø6.35)
Example: 70 Type
● Sample tubing lengths
L = 35 m 1 = 5 m
L1 = 10 m 2 = 5 m
L2 = 5 m 3 = 5 m
4 = 10 m
● Find the liquid tube size from Table 1-7.
L : ø9.52 (70 type)
L1 : ø9.52 (Total type capacity of indoor unit 36)
L2 : ø9.52 (Total type capacity of indoor unit 36)
1 – 4 : ø6.35
● The amount of additional on-site refrigerant charge is found by
subtracting the outdoor unit charge-less refrigerant amount from
the total charge amount for all tube sizes.
ø9.52 → L
: 35 m
ø9.52 → L1 + L2
: (10 + 5) m
ø6.35 → 1 – 4 : (5 + 5 + 5 + 10) m × 20 g / m =
Outdoor unit charge-less refrigerant amount
● The amount of additional on-site refrigerant charge is 1,300 g.
Table 1-8
Outdoor Unit Type
Outdoor Unit Amount of
Chargeless Refrigerant
Big_PAC_eng.indb 10 Big_PAC_eng.indb 10
Double-Twin distribution tube (L1, L2)
Main tubing (L)
Total type capacity of indoor unit connected after
the branch
70 90
ø25.4
ø9.52 ø12.7
40 g 80 g
– Outdoor unit charge-less refrigerant amount (g)
= 40X (a) + 40X (b) + 20X (c) – 1200 (70 type)
– Outdoor unit charge-less refrigerant amount (g)
= 80X (a) + 40X (b) + 20X (c) – 2400 (90 type)
Refrigerant charge per 1 m of actual length = 40 g/m
Refrigerant charge per 1 m of actual length = 80 g/m
Refrigerant charge per 1 m of actual length = 40 g/m
Refrigerant charge per 1 m of actual length = 20 g/m
× 40 g / m = 1400
× 40 g / m =
600
500
–1200
Total +1300
70 Type 90 Type
1200 g 2400 g
10
36 – 48
ø15.88
ø9.52
40 g
Outdoor unit (70 Type)
L
L1
1 2
Indoor unit (18 type × 4)
Indoor unit connection tube
( 1, 2, 3, 4)
25 – 48 18
ø15.88 ø12.7
ø9.52 ø6.35
40 g 20 g
L2
3 4
2009/08/26 16:33:08 2009/08/26 16:33:08