Additional Charging; Installing Insulation; Filling With Putty - Fujitsu Airstage AOU72RLAVL Installation Manual

Outdoor unit
Table of Contents


Evacuation procedure
(1) Remove the blank caps of the gas pipe and liquid pipe and check that the valves are
(2) Remove the charging port cap.
(3) Connect a vacuum pump and a pressure gauge to a charging hose and connect it to
the charging port.
(4) Activate the vacuum pump and vacuum the indoor unit and connection piping until
the pressure gauge becomes 500 microns (-100.7 kPa).
Evacuate from both the gas pipe and the liquid pipe.
(5) Continue evacuating the system for 1 hour after the pressure gauge reads 500
microns (-100.7 kPa).
(6) Remove the charging hose and reinstall the charging port cap.

8.3. Additional charging

Do not turn on the power unless all operations are complete.
After evacuating the system, add refrigerant.
Do not charge the system with a refrigerant other than R410A.
Always keep to the limit on the total amount of refrigerant. Exceeding the limit on the
total amount of refrigerant will lead to malfunction during charging of refrigerant.
Do not reuse recovered refrigerant.
Use an electronic scale to measure the charging amount of refrigerant.
Adding more refrigerant than the specified amount will cause a malfunction.
Charge refrigerant using the liquid pipe.
Adding refrigerant through the gas pipe will cause a malfunction.
Add refrigerant by charging the system with the refrigerant in the liquid state. If the
refrigerant cylinder is equipped with a siphon, it is not necessary to place the cylinder
Check if the steel cylinder has a siphon installed or not before filling. (There is an indica-
tion "with siphon for filling liquid" on the steel cylinder.)
Filling method
for cylinder with
Filling method for
other cylinders
Be sure to use the special tools for R410A for pressure resistance and to avoid mixing
of impure substances.
If the units are further apart than the maximum pipe length, correct operation cannot be
Make sure to back closing valve after refrigerant charging. Otherwise, the compressor
may fail.
Minimize refrigerant release to the air. Excessive release is prohibited under the Freon
Collection and Destruction Law.
8.3.1 Procedure for charging the system with refrigerant
(1) Remove the charging port cap from the liquid pipe.
(2) Attach a charging hose to the refrigerant cylinder, and connect it to the charging port.
(3) Add refrigerant by calculating the additional refrigerant volume in accordance with
the calculation formula indicated below.
(4) Remove the charging hose and install the charging port cap.
(5) Remove the blank caps (gas pipe and liquid pipe) and open the valves.
(6) Close the blank caps.
(7) After adding refrigerant, indicate the added charging volume on the unit.
* Tighten the blank caps and charging port caps to the torque values specified in the
Table A. To open and close the valves, use an M4 hexagon wrench.
8.3.2 Checking total amount of refrigerant and calculating the
amount of refrigerant charge to be added
• The amount of refrigerant charge to be added is the total value of the basic refrigerant
charge amount and the value calculated from the length of the liquid pipe.
• Round up the value to 2 decimal places.
Factory charged
amount [lbs (kg)]
24.25 (11.0)
24.25 (11.0)
24.25 (11.0)
Set the cylinder vertical and fill with
the liquid.
(Liquid can be filled without turning
bottom up with the siphon inside.)
Turn bottom up and fill with liquid.
(Be careful to avoid turning over the
Diameter of liquid
Additional amount for
pipe [in (mm)]
pipe length [lbs/ft (kg/m)]
Ø 1/4 (6.35)
0.014 (0.021)
Ø 3/8 (9.52)
0.039 (0.058)
Ø 1/2 (12.70)
0.077 (0.114)
Ø 5/8 (15.88)
0.120 (0.178)
Ø 3/4 (19.05)
0.180 (0.268)
(1) Calculation of additional amount for pipe length
Total length of ø 1/2 in
a × 0.077
(12.70 mm) liquid pipe
(× 0.114)
[lbs/ft (kg/m)]
A =
ft (m)
lbs (kg)
Total length of ø 1/4 in
a × 0.014
(6.35 mm) liquid pipe
(× 0.021)
[lbs/ft (kg/m)]
ft (m)
lbs (kg)
(2) Calculation of total refrigerant amount
C = A+B =
lbs (kg)
Check the total refrigerant amount under the following conditions
Total amount of refrig-
Outdoor unit: AOU72RLAVL
(1) Calculation of additional amount for outdoor unit
If liquid pipe piping length is the following
Ø 1/2 in: 164 ft, Ø 3/8 in: 82 ft, Ø 1/4 in: 49 ft
(Ø 12.70 mm: 50 m, Ø 9.52 mm: 25 m, Ø 6.35 mm: 15 m)
Additional charge volume:
A = 164 ft × 0.077 lbs/ft + 82 ft × 0.039 lbs/ft +49 ft × 0.014 lbs/ft = 16.512 lbs ≈
16.51 lbs
(A = 50 m × 0.114 kg/m + 25 m × 0.058 kg/m +15 m × 0.021 kg/m = 7.465 kg ≈ 7.47 kg)
(2) Check the total amount of refrigerant
= A + B = 16.51 lbs + 24.25 lbs = 40.76 lbs ≤ 44.09 lbs
(C = A + B = 7.47 kg + 11.0 kg = 18.47 kg ≤ 20.0 kg)
→No problem if the above condition is satisfied.

8.4. Installing insulation

• Install insulation material after conducting the "8.1 Sealing test".
• To prevent condensation and water droplets, install insulation material on the refrigerant
• Refer to the table to determine the thickness of the insulation material.
• If the outdoor unit is installed at a level that is higher than the indoor unit, the water that
has condensed in the 3-way valve of the outdoor unit could travel to the indoor unit.
Therefore, use putty in the space between the pipe and the insulation to prevent the
entry of water.
Table. Selection of insulation
(Use an insulation material with equal heat transmission rate or below 0.040
Insulation material minimum thickness (mm)
Relative humidity
≤ 70%
Pipe diameter
1/4 (6.35)
5/16 (8)
[in (mm)]
3/8 (9.52)
3/8 (9)
1/2 (12.70)
3/8 (10)
5/8 (15.88)
3/8 (10)
3/4 (19.05)
3/8 (10)
7/8 (22.22)
7/16 (11)
1-1/8 (28.58)
7/16 (11)
* When an ambient temperature and relative humidity exceed 90 °F (32 °C) (DB) and
85% respectively, please strengthen heat insulation of refrigerant pipe.

8.5. Filling with putty

Fill the piping holes and wiring holes with putty
(locally purchased) to avoid any gap (Fig A). If
small animals such as insects enter the external
unit, a short circuit may be caused near electrical
components in the service panel.
If the outdoor unit is installed at a level that is higher
than the indoor unit, the water that has condensed
in the 3-way valve of the outdoor unit could travel
to the indoor unit. Therefore, use putty in the space
between the pipe and the insulation to prevent the
entry of water to the indoor units.
Total length of ø 3/8 in
a × 0.039
(9.52 mm) liquid pipe
(× 0.058)
[lbs/ft (kg/m)]
ft (m)
lbs (kg)
lbs (kg)
(Round up A to 2 decimal place)
(B: Factory charged amount)
Computational formula
C ≤ 44.09 lbs (20.0 kg)
C ≤ 44.09 lbs (20.0 kg)
C ≤ 56.44 lbs (25.6 kg)
≤ 75%
≤ 80%
≤ 85%
3/8 (10)
1/2 (13)
11/16 (17)
7/16 (11)
9/16 (14)
11/16 (18)
1/2 (12)
9/16 (15)
3/4 (19)
1/2 (12)
5/8 (16)
13/16 (20)
1/2 (13)
5/8 (16)
13/16 (21)
1/2 (13)
11/16 (17)
7/8 (22)
9/16 (14)
11/16 (18)
7/8 (23)
Fig. A

Hide quick links:


Table of Contents

This manual is also suitable for:

Airstage aou96rlavlAirstage aou120rlavl

Table of Contents