1-15. Example Of Tubing Size Selection And; Refrigerant Charge Amount - Panasonic U-72MF1U9 Installation Instructions Manual

1-15. Example of Tubing Size Selection and Refrigerant Charge Amount
Additional refrigerant charging
Based on the values in Tables 1-3, 4, 5, 9 and 10-2 use the liquid tubing size and length, and calculate the amount of additional
refrigerant charge using the formula below.
Required additional 3.93 × (a) + 2.78 × (b) + 1.99 × (c) + 1.38 × (d) + 0.602 × (e) + 0.279 × (f) + Necessary amount of
=
refrigerant charge (oz) additional refrigerant charge per outdoor unit
(a) : Liquid tubing Total length of ø7/8" (ft.)
(b) : Liquid tubing Total length of ø3/4" (ft.)
(c) : Liquid tubing Total length of ø5/8" (ft.)
●
Charging procedure
Be sure to charge with R410A refrigerant in liquid form.
1. After performing a vacuum, charge with refrigerant from the liquid tubing side. At this time, all valves must be in the "fully
closed" position.
2. If it was not possible to charge the designated amount, operate the system in Cooling mode while charging with refrigerant
from the gas tubing side. (This is performed at the time of the test run. For this, all valves must be in the "fully open" position.
However if only one outdoor unit is installed, a balance tube is not used. Therefore, leave the valves fully closed.)
Charge with R410A refrigerant in liquid form.
With R410A refrigerant, charge while adjusting the amount being fed a little at a time in order to prevent liquid refrigerant from
backing up.
●
After charging is completed, turn all valves to the "fully open" position.
●
Replace the tubing covers as they were before.
1. R410A additional charging absolutely
must be done through liquid charging.
CAUTION
2. The R410A refrigerant cylinder has a gray
base color, and the top part is pink.
3. The R410A refrigerant cylinder includes a
siphon tube. Check that the siphon tube is
present. (This is indicated on the label at
the top of the cylinder.)
4. Due to differences in the refrigerant,
pressure, and refrigerant oil involved in
installation, it is not possible in some
cases to use the same tools for R22 and
for R410A.
Example:
Outdoor unit
96 type 96 type
B A
LA
● Example of each tubing length
Main tubing
LA = 131 ft.
LB = 16 ft.
LC = 16 ft.
(d) : Liquid tubing
(e) : Liquid tubing
( f ) : Liquid tubing
LC
LB
1 2 3
48 type 48 type 48 type
Distribution joint tubing
Outdoor side
A = 7 ft.
B = 7 ft.
18
Total length of ø1/2" (ft.)
Total length of ø3/8" (ft.)
Total length of ø1/4" (ft.)
Balance tube
Use a flathead screwdriver
and open by turning the part
with the screw groove to the
right, from " " to " "
Liquid tube
Use a hex wrench (width 5/32 inch)
and turn to the left to open.
Discharge tube
Use a flathead screwdriver
and open by turning the part
with the screw groove to the
right, from " " to " "
4
36 type
Indoor side
1 = 98 ft.
2 = 16 ft.
3 = 16 ft.
4 = 65 ft.
Suction tube
Use a flathead screwdriver
and open by turning the part
with the screw groove to the
right, from " " to " "